freebsd-skq/cddl/contrib/opensolaris/cmd/zfs/zfs.8

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.Dd July 30, 2015
.Dt ZFS 8
.Os
.Sh NAME
.Nm zfs
.Nd configures ZFS file systems
.Sh SYNOPSIS
.Nm
.Op Fl \&?
.Nm
.Cm create
.Op Fl pu
.Oo Fl o Ar property Ns = Ns Ar value Oc Ns ... Ar filesystem
.Nm
.Cm create
.Op Fl ps
.Op Fl b Ar blocksize
.Oo Fl o Ar property Ns = Ns Ar value Oc Ns ...
.Fl V
.Ar size volume
.Nm
.Cm destroy
.Op Fl fnpRrv
.Ar filesystem Ns | Ns Ar volume
.Nm
.Cm destroy
.Op Fl dnpRrv
.Sm off
.Ar filesystem Ns | Ns volume
.Ns @snap
.Op % Ns Ar snap
.Op , Ns Ar snap Op % Ns Ar snap
.Op , Ns ...
.Sm on
.Nm
.Cm destroy
.Ar filesystem Ns | Ns Ar volume Ns # Ns Ar bookmark
.Nm
.Cm snapshot Ns | Ns Cm snap
.Op Fl r
.Oo Fl o Ar property Ns = Ns Ar value Oc Ns ...
.Ar filesystem@snapname Ns | Ns Ar volume@snapname
.Ar filesystem@snapname Ns | Ns Ar volume@snapname Ns ...
.Nm
.Cm rollback
.Op Fl rRf
.Ar snapshot
.Nm
.Cm clone
.Op Fl p
.Oo Fl o Ar property Ns = Ns Ar value Oc Ns ...
.Ar snapshot filesystem Ns | Ns Ar volume
.Nm
.Cm promote
.Ar clone-filesystem
.Nm
.Cm rename
.Op Fl f
.Ar filesystem Ns | Ns Ar volume Ns | Ns Ar snapshot
.Ar filesystem Ns | Ns Ar volume Ns | Ns Ar snapshot
.Nm
.Cm rename
.Op Fl f
.Fl p
.Ar filesystem Ns | Ns Ar volume
.Ar filesystem Ns | Ns Ar volume
.Nm
.Cm rename
.Fl r
.Ar snapshot snapshot
.Nm
.Cm rename
.Fl u
.Op Fl p
.Ar filesystem filesystem
.Nm
.Cm list
.Op Fl r Ns | Ns Fl d Ar depth
.Op Fl Hp
.Op Fl o Ar property Ns Oo , Ns property Ns Oc Ns ...
.Op Fl t Ar type Ns Oo , Ns type Ns Oc Ns ...
.Oo Fl s Ar property Oc Ns ...
.Oo Fl S Ar property Oc Ns ...
.Ar filesystem Ns | Ns Ar volume Ns | Ns Ar snapshot
.Nm
.Cm set
.Ar property Ns = Ns Ar value
.Ar filesystem Ns | Ns Ar volume Ns | Ns Ar snapshot Ns ...
.Nm
.Cm get
.Op Fl r Ns | Ns Fl d Ar depth
.Op Fl Hp
.Op Fl o Ar all | field Ns Oo , Ns Ar field Oc Ns ...
.Op Fl t Ar type Ns Oo Ns , Ar type Oc Ns ...
.Op Fl s Ar source Ns Oo Ns , Ns Ar source Oc Ns ...
.Ar all | property Ns Oo Ns , Ns Ar property Oc Ns ...
.Ar filesystem Ns | Ns Ar volume Ns | Ns Ar snapshot Ns ...
.Nm
.Cm inherit
.Op Fl rS
.Ar property
.Ar filesystem Ns | Ns Ar volume Ns | Ns Ar snapshot Ns ...
.Nm
.Cm upgrade
.Op Fl v
.Nm
.Cm upgrade
.Op Fl r
.Op Fl V Ar version
.Fl a | Ar filesystem
.Nm
.Cm userspace
.Op Fl Hinp
.Op Fl o Ar field Ns Oo , Ns Ar field Oc Ns ...
.Oo Fl s Ar field Oc Ns ...
.Oo Fl S Ar field Oc Ns ...
.Op Fl t Ar type Ns Oo Ns , Ns Ar type Oc Ns ...
.Ar filesystem Ns | Ns Ar snapshot
.Nm
.Cm groupspace
.Op Fl Hinp
.Op Fl o Ar field Ns Oo , Ns field Oc Ns ...
.Oo Fl s Ar field Oc Ns ...
.Oo Fl S Ar field Oc Ns ...
.Op Fl t Ar type Ns Oo Ns , Ns Ar type Oc Ns ...
.Ar filesystem Ns | Ns Ar snapshot
.Nm
.Cm mount
.Nm
.Cm mount
.Op Fl vO
.Op Fl o Ar property Ns Oo , Ns Ar property Oc Ns ...
.Fl a | Ar filesystem
.Nm
.Cm unmount Ns | Ns Cm umount
.Op Fl f
.Fl a | Ar filesystem Ns | Ns Ar mountpoint
.Nm
.Cm share
.Fl a | Ar filesystem
.Nm
.Cm unshare
.Fl a | Ar filesystem Ns | Ns Ar mountpoint
.Nm
.Cm bookmark
.Ar snapshot
.Ar bookmark
.Nm
.Cm send
.Op Fl DnPpRveL
.Op Fl i Ar snapshot | Fl I Ar snapshot
.Ar snapshot
.Nm
.Cm send
.Op Fl eL
.Op Fl i Ar snapshot Ns | Ns bookmark
.Ar filesystem Ns | Ns Ar volume Ns | Ns Ar snapshot
.Nm
.Cm receive Ns | Ns Cm recv
.Op Fl vnFu
.Ar filesystem Ns | Ns Ar volume Ns | Ns Ar snapshot
.Nm
.Cm receive Ns | Ns Cm recv
.Op Fl vnFu
.Op Fl d | e
.Ar filesystem
.Nm
.Cm allow
.Ar filesystem Ns | Ns Ar volume
.Nm
.Cm allow
.Op Fl ldug
.Ar user Ns | Ns Ar group Ns Oo Ns , Ns Ar user Ns | Ns Ar group Oc Ns ...
.Ar perm Ns | Ns Ar @setname Ns
.Oo Ns , Ns Ar perm Ns | Ns Ar @setname Oc Ns ...
.Ar filesystem Ns | Ns Ar volume
.Nm
.Cm allow
.Op Fl ld
.Fl e Ns | Ns Cm everyone
.Ar perm Ns | Ns Ar @setname Ns Op Ns , Ns Ar perm Ns | Ns Ar @setname Ns
.Ns ...
.Ar filesystem Ns | Ns Ar volume
.Nm
.Cm allow
.Fl c
.Ar perm Ns | Ns Ar @setname Ns Op Ns , Ns Ar perm Ns | Ns Ar @setname Ns
.Ns ...
.Ar filesystem Ns | Ns Ar volume
.Nm
.Cm allow
.Fl s
.Ar @setname
.Ar perm Ns | Ns Ar @setname Ns Op Ns , Ns Ar perm Ns | Ns Ar @setname Ns
.Ns ...
.Ar filesystem Ns | Ns Ar volume
.Nm
.Cm unallow
.Op Fl rldug
.Ar user Ns | Ns Ar group Ns Oo Ns , Ns Ar user Ns | Ns Ar group Oc Ns ...
.Oo Ar perm Ns | Ns Ar @setname Ns Op , Ns Ar perm Ns | Ns Ar @setname Ns
.Ns ... Oc
.Ar filesystem Ns | Ns Ar volume
.Nm
.Cm unallow
.Op Fl rld
.Fl e Ns | Ns Cm everyone
.Oo Ar perm Ns | Ns Ar @setname Ns Op , Ns Ar perm Ns | Ns Ar @setname Ns
.Ns ... Oc
.Ar filesystem Ns | Ns Ar volume
.Nm
.Cm unallow
.Op Fl r
.Fl c
.Oo Ar perm Ns | Ns Ar @setname Ns Op , Ns Ar perm Ns | Ns Ar @setname Ns
.Ns ... Oc
.Ar filesystem Ns | Ns Ar volume
.Nm
.Cm unallow
.Op Fl r
.Fl s
.Ar @setname
.Oo Ar perm Ns | Ns Ar @setname Ns Op , Ns Ar perm Ns | Ns Ar @setname Ns
.Ns ... Oc
.Ar filesystem Ns | Ns Ar volume
.Nm
.Cm hold
.Op Fl r
.Ar tag snapshot Ns ...
.Nm
.Cm holds
.Op Fl r
.Ar snapshot Ns ...
.Nm
.Cm release
.Op Fl r
.Ar tag snapshot Ns ...
.Nm
.Cm diff
.Op Fl FHt
.Ar snapshot
.Op Ar snapshot Ns | Ns Ar filesystem
.Nm
.Cm jail
.Ar jailid Ns | Ns Ar jailname filesystem
.Nm
.Cm unjail
.Ar jailid Ns | Ns Ar jailname filesystem
.Sh DESCRIPTION
The
.Nm
command configures
.Tn ZFS
datasets within a
.Tn ZFS
storage pool, as described in
.Xr zpool 8 .
A dataset is identified by a unique path within the
.Tn ZFS
namespace. For example:
.Bd -ragged -offset 4n
.No pool/ Ns Brq filesystem,volume,snapshot
.Ed
.Pp
where the maximum length of a dataset name is
.Dv MAXNAMELEN
(256 bytes).
.Pp
A dataset can be one of the following:
.Bl -hang -width 12n
.It Sy file system
A
.Tn ZFS
dataset of type
.Em filesystem
can be mounted within the standard system namespace and behaves like other file
systems. While
.Tn ZFS
file systems are designed to be
.Tn POSIX
compliant, known issues exist that prevent compliance in some cases.
Applications that depend on standards conformance might fail due to nonstandard
behavior when checking file system free space.
.It Sy volume
A logical volume exported as a raw or block device. This type of dataset should
only be used under special circumstances. File systems are typically used in
most environments.
.It Sy snapshot
A read-only version of a file system or volume at a given point in time. It is
specified as
.Em filesystem@name
or
.Em volume@name .
.El
.Ss ZFS File System Hierarchy
A
.Tn ZFS
storage pool is a logical collection of devices that provide space for
datasets. A storage pool is also the root of the
.Tn ZFS
file system hierarchy.
.Pp
The root of the pool can be accessed as a file system, such as mounting and
unmounting, taking snapshots, and setting properties. The physical storage
characteristics, however, are managed by the
.Xr zpool 8
command.
.Pp
See
.Xr zpool 8
for more information on creating and administering pools.
.Ss Snapshots
A snapshot is a read-only copy of a file system or volume. Snapshots can be
created extremely quickly, and initially consume no additional space within the
pool. As data within the active dataset changes, the snapshot consumes more
data than would otherwise be shared with the active dataset.
.Pp
Snapshots can have arbitrary names. Snapshots of volumes can be cloned or
rolled back, but cannot be accessed independently.
.Pp
File system snapshots can be accessed under the
.Pa \&.zfs/snapshot
directory in the root of the file system. Snapshots are automatically mounted
on demand and may be unmounted at regular intervals. The visibility of the
.Pa \&.zfs
directory can be controlled by the
.Sy snapdir
property.
.Ss Clones
A clone is a writable volume or file system whose initial contents are the same
as another dataset. As with snapshots, creating a clone is nearly
instantaneous, and initially consumes no additional space.
.Pp
Clones can only be created from a snapshot. When a snapshot is cloned, it
creates an implicit dependency between the parent and child. Even though the
clone is created somewhere else in the dataset hierarchy, the original snapshot
cannot be destroyed as long as a clone exists. The
.Sy origin
property exposes this dependency, and the
.Cm destroy
command lists any such dependencies, if they exist.
.Pp
The clone parent-child dependency relationship can be reversed by using the
.Cm promote
subcommand. This causes the "origin" file system to become a clone of the
specified file system, which makes it possible to destroy the file system that
the clone was created from.
.Ss Mount Points
Creating a
.Tn ZFS
file system is a simple operation, so the number of file systems per system is
likely to be numerous. To cope with this,
.Tn ZFS
automatically manages mounting and unmounting file systems without the need to
edit the
.Pa /etc/fstab
file. All automatically managed file systems are mounted by
.Tn ZFS
at boot time.
.Pp
By default, file systems are mounted under
.Pa /path ,
where
.Ar path
is the name of the file system in the
.Tn ZFS
namespace. Directories are created and destroyed as needed.
.Pp
A file system can also have a mount point set in the
.Sy mountpoint
property. This directory is created as needed, and
.Tn ZFS
automatically mounts the file system when the
.Qq Nm Cm mount Fl a
command is invoked (without editing
.Pa /etc/fstab ) .
The
.Sy mountpoint
property can be inherited, so if
.Em pool/home
has a mount point of
.Pa /home ,
then
.Em pool/home/user
automatically inherits a mount point of
.Pa /home/user .
.Pp
A file system
.Sy mountpoint
property of
.Cm none
prevents the file system from being mounted.
.Pp
If needed,
.Tn ZFS
file systems can also be managed with traditional tools
.Pq Xr mount 8 , Xr umount 8 , Xr fstab 5 .
If a file system's mount point is set to
.Cm legacy ,
.Tn ZFS
makes no attempt to manage the file system, and the administrator is
responsible for mounting and unmounting the file system.
.Ss Jails
.No A Tn ZFS
dataset can be attached to a jail by using the
.Qq Nm Cm jail
subcommand. You cannot attach a dataset to one jail and the children of the
same dataset to another jails. To allow management of the dataset from within
a jail, the
.Sy jailed
property has to be set and the jail needs access to the
.Pa /dev/zfs
device. The
.Sy quota
property cannot be changed from within a jail. See
.Xr jail 8
for information on how to allow mounting
.Tn ZFS
datasets from within a jail.
.Pp
.No A Tn ZFS
dataset can be detached from a jail using the
.Qq Nm Cm unjail
subcommand.
.Pp
After a dataset is attached to a jail and the jailed property is set, a jailed
file system cannot be mounted outside the jail, since the jail administrator
might have set the mount point to an unacceptable value.
.Ss Deduplication
Deduplication is the process for removing redundant data at the block-level,
reducing the total amount of data stored. If a file system has the
.Cm dedup
property enabled, duplicate data blocks are removed synchronously. The result
is that only unique data is stored and common components are shared among
files.
.Ss Native Properties
Properties are divided into two types, native properties and user-defined (or
"user") properties. Native properties either export internal statistics or
control
.Tn ZFS
behavior. In addition, native properties are either editable or read-only. User
properties have no effect on
.Tn ZFS
behavior, but you can use them to annotate datasets in a way that is meaningful
in your environment. For more information about user properties, see the
.Qq Sx User Properties
section, below.
.Pp
Every dataset has a set of properties that export statistics about the dataset
as well as control various behaviors. Properties are inherited from the parent
unless overridden by the child. Some properties apply only to certain types of
datasets (file systems, volumes, or snapshots).
.Pp
The values of numeric properties can be specified using human-readable suffixes
(for example,
.Sy k , KB , M , Gb ,
and so forth, up to
.Sy Z
for zettabyte). The following are all valid (and equal) specifications:
.Bd -ragged -offset 4n
1536M, 1.5g, 1.50GB
.Ed
.Pp
The values of non-numeric properties are case sensitive and must be lowercase,
except for
.Sy mountpoint , sharenfs , No and Sy sharesmb .
.Pp
The following native properties consist of read-only statistics about the
dataset. These properties can be neither set, nor inherited. Native properties
apply to all dataset types unless otherwise noted.
.Bl -tag -width 2n
.It Sy available
The amount of space available to the dataset and all its children, assuming
that there is no other activity in the pool. Because space is shared within a
pool, availability can be limited by any number of factors, including physical
pool size, quotas, reservations, or other datasets within the pool.
.Pp
This property can also be referred to by its shortened column name,
.Sy avail .
.It Sy compressratio
For non-snapshots, the compression ratio achieved for the
.Sy used
space of this dataset, expressed as a multiplier.  The
.Sy used
property includes descendant datasets, and, for clones, does not include
the space shared with the origin snapshot.  For snapshots, the
.Sy compressratio
is the same as the
.Sy refcompressratio
property. Compression can be turned on by running:
.Qq Nm Cm set compression=on Ar dataset
The default value is
.Cm off .
.It Sy creation
The time this dataset was created.
.It Sy clones
For snapshots, this property is a comma-separated list of filesystems or
volumes which are clones of this snapshot.  The clones'
.Sy origin
property is this snapshot.  If the
.Sy clones
property is not empty, then this snapshot can not be destroyed (even with the
.Fl r
or
.Fl f
options).
.It Sy defer_destroy
This property is
.Cm on
if the snapshot has been marked for deferred destroy by using the
.Qq Nm Cm destroy -d
command. Otherwise, the property is
.Cm off .
.It Sy filesystem_count
The total number of filesystems and volumes that exist under this location in the
dataset tree.
This value is only available when a
.Sy filesystem_limit
has
been set somewhere in the tree under which the dataset resides.
.It Sy logicalreferenced
The amount of space that is
.Qq logically
accessible by this dataset.
See the
.Sy referenced
property.
The logical space ignores the effect of the
.Sy compression
and
.Sy copies
properties, giving a quantity closer to the amount of data that applications
see.
However, it does include space consumed by metadata.
.Pp
This property can also be referred to by its shortened column name,
.Sy lrefer .
.It Sy logicalused
The amount of space that is
.Qq logically
consumed by this dataset and all its descendents.
See the
.Sy used
property.
The logical space ignores the effect of the
.Sy compression
and
.Sy copies
properties, giving a quantity closer to the amount of data that applications
see.
.Pp
This property can also be referred to by its shortened column name,
.Sy lused .
.It Sy mounted
For file systems, indicates whether the file system is currently mounted. This
property can be either
.Cm yes
or
.Cm no .
.It Sy origin
For cloned file systems or volumes, the snapshot from which the clone was
created. See also the
.Sy clones
property.
.It Sy referenced
The amount of data that is accessible by this dataset, which may or may not be
shared with other datasets in the pool. When a snapshot or clone is created, it
initially references the same amount of space as the file system or snapshot it
was created from, since its contents are identical.
.Pp
This property can also be referred to by its shortened column name,
.Sy refer .
.It Sy refcompressratio
The compression ratio achieved for the
.Sy referenced
space of this dataset, expressed as a multiplier.  See also the
.Sy compressratio
property.
.It Sy snapshot_count
The total number of snapshots that exist under this location in the dataset tree.
This value is only available when a
.Sy snapshot_limit
has been set somewhere
in the tree under which the dataset resides.
.It Sy type
The type of dataset:
.Sy filesystem , volume , No or Sy snapshot .
.It Sy used
The amount of space consumed by this dataset and all its descendents. This is
the value that is checked against this dataset's quota and reservation. The
space used does not include this dataset's reservation, but does take into
account the reservations of any descendent datasets. The amount of space that a
dataset consumes from its parent, as well as the amount of space that are freed
if this dataset is recursively destroyed, is the greater of its space used and
its reservation.
.Pp
When snapshots (see the
.Qq Sx Snapshots
section) are created, their space is
initially shared between the snapshot and the file system, and possibly with
previous snapshots. As the file system changes, space that was previously
shared becomes unique to the snapshot, and counted in the snapshot's space
used. Additionally, deleting snapshots can increase the amount of space unique
to (and used by) other snapshots.
.Pp
The amount of space used, available, or referenced does not take into account
pending changes. Pending changes are generally accounted for within a few
seconds. Committing a change to a disk using
.Xr fsync 2
or
.Sy O_SYNC
does not necessarily guarantee that the space usage information is updated
immediately.
.It Sy usedby*
The
.Sy usedby*
properties decompose the
.Sy used
properties into the various reasons that space is used. Specifically,
.Sy used No =
.Sy usedbysnapshots + usedbydataset + usedbychildren + usedbyrefreservation .
These properties are only available for datasets created
with
.Tn ZFS
pool version 13 pools and higher.
.It Sy usedbysnapshots
The amount of space consumed by snapshots of this dataset. In particular, it is
the amount of space that would be freed if all of this dataset's snapshots were
destroyed. Note that this is not simply the sum of the snapshots'
.Sy used
properties because space can be shared by multiple snapshots.
.It Sy usedbydataset
The amount of space used by this dataset itself, which would be freed if the
dataset were destroyed (after first removing any
.Sy refreservation
and destroying any necessary snapshots or descendents).
.It Sy usedbychildren
The amount of space used by children of this dataset, which would be freed if
all the dataset's children were destroyed.
.It Sy usedbyrefreservation
The amount of space used by a
.Sy refreservation
set on this dataset, which would be freed if the
.Sy refreservation
was removed.
.It Sy userused@ Ns Ar user
The amount of space consumed by the specified user in this dataset. Space is
charged to the owner of each file, as displayed by
.Qq Nm ls Fl l .
The amount of space charged is displayed by
.Qq Nm du
and
.Qq Nm ls Fl s .
See the
.Qq Nm Cm userspace
subcommand for more information.
.Pp
Unprivileged users can access only their own space usage. The root user, or a
user who has been granted the
.Sy userused
privilege with
.Qq Nm Cm allow ,
can access everyone's usage.
.Pp
The
.Sy userused@ Ns ...
properties are not displayed by
.Qq Nm Cm get all .
The user's name must be appended after the
.Sy @
symbol, using one of the following forms:
.Bl -bullet -offset 2n
.It
POSIX name (for example,
.Em joe )
.It
POSIX numeric ID (for example,
.Em 1001 )
.El
.It Sy userrefs
This property is set to the number of user holds on this snapshot. User holds
are set by using the
.Qq Nm Cm hold
command.
.It Sy groupused@ Ns Ar group
The amount of space consumed by the specified group in this dataset. Space is
charged to the group of each file, as displayed by
.Nm ls Fl l .
See the
.Sy userused@ Ns Ar user
property for more information.
.Pp
Unprivileged users can only access their own groups' space usage. The root
user, or a user who has been granted the
.Sy groupused
privilege with
.Qq Nm Cm allow ,
can access all groups' usage.
.It Sy volblocksize Ns = Ns Ar blocksize
For volumes, specifies the block size of the volume. The
.Ar blocksize
cannot be changed once the volume has been written, so it should be set at
volume creation time. The default
.Ar blocksize
for volumes is 8 Kbytes. Any
power of 2 from 512 bytes to 128 Kbytes is valid.
.Pp
This property can also be referred to by its shortened column name,
.Sy volblock .
.It Sy written
The amount of
.Sy referenced
space written to this dataset since the previous snapshot.
.It Sy written@ Ns Ar snapshot
The amount of
.Sy referenced
space written to this dataset since the specified snapshot.  This is the space
that is referenced by this dataset but was not referenced by the specified
snapshot.
.Pp
The
.Ar snapshot
may be specified as a short snapshot name (just the part after the
.Sy @ ) ,
in which case it will be interpreted as a snapshot in the same filesystem as
this dataset. The
.Ar snapshot
may be a full snapshot name
.Pq Em filesystem@snapshot ,
which for clones may be a snapshot in the origin's filesystem (or the origin of
the origin's filesystem, etc).
.El
.Pp
The following native properties can be used to change the behavior of a
.Tn ZFS
dataset.
.Bl -tag -width 2n
.It Xo
.Sy aclinherit Ns = Ns Cm discard |
.Cm noallow |
.Cm restricted |
.Cm passthrough |
.Cm passthrough-x
.Xc
Controls how
.Tn ACL
entries are inherited when files and directories are created. A file system
with an
.Sy aclinherit
property of
.Cm discard
does not inherit any
.Tn ACL
entries. A file system with an
.Sy aclinherit
property value of
.Cm noallow
only inherits inheritable
.Tn ACL
entries that specify "deny" permissions. The property value
.Cm restricted
(the default) removes the
.Em write_acl
and
.Em write_owner
permissions when the
.Tn ACL
entry is inherited. A file system with an
.Sy aclinherit
property value of
.Cm passthrough
inherits all inheritable
.Tn ACL
entries without any modifications made to the
.Tn ACL
entries when they are inherited. A file system with an
.Sy aclinherit
property value of
.Cm passthrough-x
has the same meaning as
.Cm passthrough ,
except that the
.Em owner@ , group@ , No and Em everyone@ Tn ACE Ns s
inherit the execute permission only if the file creation mode also requests the
execute bit.
.Pp
When the property value is set to
.Cm passthrough ,
files are created with a mode determined by the inheritable
.Tn ACE Ns s.
If no inheritable
.Tn ACE Ns s
exist that affect the mode, then the mode is set in accordance to the requested
mode from the application.
.It Sy aclmode Ns = Ns Cm discard | groupmask | passthrough | restricted
Controls how an
.Tn ACL
is modified during
.Xr chmod 2 .
A file system with an
.Sy aclmode
property of
.Cm discard
(the default) deletes all
.Tn ACL
entries that do not represent the mode of the file. An
.Sy aclmode
property of
.Cm groupmask
reduces permissions granted in all
.Em ALLOW
entries found in the
.Tn ACL
such that they are no greater than the group permissions specified by
.Xr chmod 2 .
A file system with an
.Sy aclmode
property of
.Cm passthrough
indicates that no changes are made to the
.Tn ACL
other than creating or updating the necessary
.Tn ACL
entries to represent the new mode of the file or directory.
An
.Sy aclmode
property of
.Cm restricted
will cause the
.Xr chmod 2
operation to return an error when used on any file or directory which has
a non-trivial
.Tn ACL
whose entries can not be represented by a mode.
.Xr chmod 2
is required to change the set user ID, set group ID, or sticky bits on a file
or directory, as they do not have equivalent
.Tn ACL
entries.
In order to use
.Xr chmod 2
on a file or directory with a non-trivial
.Tn ACL
when
.Sy aclmode
is set to
.Cm restricted ,
you must first remove all
.Tn ACL
entries which do not represent the current mode.
.It Sy atime Ns = Ns Cm on | off
Controls whether the access time for files is updated when they are read.
Turning this property off avoids producing write traffic when reading files and
can result in significant performance gains, though it might confuse mailers
and other similar utilities. The default value is
.Cm on .
.It Sy canmount Ns = Ns Cm on | off | noauto
If this property is set to
.Cm off ,
the file system cannot be mounted, and is ignored by
.Qq Nm Cm mount Fl a .
Setting this property to
.Cm off
is similar to setting the
.Sy mountpoint
property to
.Cm none ,
except that the dataset still has a normal
.Sy mountpoint
property, which can be inherited. Setting this property to
.Cm off
allows datasets to be used solely as a mechanism to inherit properties. One
example of setting
.Sy canmount Ns = Ns Cm off
is to have two datasets with the same
.Sy mountpoint ,
so that the children of both datasets appear in the same directory, but might
have different inherited characteristics.
.Pp
When the
.Cm noauto
value is set, a dataset can only be mounted and unmounted explicitly. The
dataset is not mounted automatically when the dataset is created or imported,
nor is it mounted by the
.Qq Nm Cm mount Fl a
command or unmounted by the
.Qq Nm Cm umount Fl a
command.
.Pp
This property is not inherited.
.It Sy checksum Ns = Ns Cm on | off | fletcher2 | fletcher4 | sha256 | noparity
Controls the checksum used to verify data integrity. The default value is
.Cm on ,
which automatically selects an appropriate algorithm (currently,
.Cm fletcher4 ,
but this may change in future releases). The value
.Cm off
disables integrity checking on user data.
The value
.Cm noparity
not only
disables integrity but also disables maintaining parity for user data.  This
setting is used internally by a dump device residing on a RAID-Z pool and should
not be used by any other dataset.
Disabling checksums is
.Em NOT
a recommended practice.
.It Sy compression Ns = Ns Cm on | off | lzjb | gzip | gzip- Ns Ar N | Cm zle | Cm lz4
Controls the compression algorithm used for this dataset. The
.Cm lzjb
compression algorithm is optimized for performance while providing decent data
compression. Setting compression to
.Cm on
uses the
.Cm lzjb
compression algorithm. The
.Cm gzip
compression algorithm uses the same compression as the
.Xr gzip 1
command. You can specify the
.Cm gzip
level by using the value
.Cm gzip- Ns Ar N
where
.Ar N
is an integer from 1 (fastest) to 9 (best compression ratio). Currently,
.Cm gzip
is equivalent to
.Cm gzip-6
(which is also the default for
.Xr gzip 1 ) .
The
.Cm zle
compression algorithm compresses runs of zeros.
.Pp
The
.Sy lz4
compression algorithm is a high-performance replacement
for the
.Sy lzjb
algorithm. It features significantly faster
compression and decompression, as well as a moderately higher
compression ratio than
.Sy lzjb ,
but can only be used on pools with
the
.Sy lz4_compress
feature set to
.Sy enabled .
See
.Xr zpool-features 7
for details on ZFS feature flags and the
.Sy lz4_compress
feature.
.Pp
This property can also be referred to by its shortened column name
.Cm compress .
Changing this property affects only newly-written data.
.It Sy copies Ns = Ns Cm 1 | 2 | 3
Controls the number of copies of data stored for this dataset. These copies are
in addition to any redundancy provided by the pool, for example, mirroring or
RAID-Z. The copies are stored on different disks, if possible. The space used
by multiple copies is charged to the associated file and dataset, changing the
.Sy used
property and counting against quotas and reservations.
.Pp
Changing this property only affects newly-written data. Therefore, set this
property at file system creation time by using the
.Fl o Cm copies= Ns Ar N
option.
.It Sy dedup Ns = Ns Cm on | off | verify | sha256 Ns Op Cm ,verify
Configures deduplication for a dataset. The default value is
.Cm off .
The default deduplication checksum is
.Cm sha256
(this may change in the future).
When
.Sy dedup
is enabled, the checksum defined here overrides the
.Sy checksum
property. Setting the value to
.Cm verify
has the same effect as the setting
.Cm sha256,verify .
.Pp
If set to
.Cm verify ,
.Tn ZFS
will do a byte-to-byte comparsion in case of two blocks having the same
signature to make sure the block contents are identical.
.It Sy devices Ns = Ns Cm on | off
The
.Sy devices
property is currently not supported on
.Fx .
.It Sy exec Ns = Ns Cm on | off
Controls whether processes can be executed from within this file system. The
default value is
.Cm on .
.It Sy mlslabel Ns = Ns Ar label | Cm none
The
.Sy mlslabel
property is currently not supported on
.Fx .
.It Sy filesystem_limit Ns = Ns Ar count | Cm none
Limits the number of filesystems and volumes that can exist under this point in
the dataset tree.
The limit is not enforced if the user is allowed to change
the limit.
Setting a
.Sy filesystem_limit
on a descendent of a filesystem that
already has a
.Sy filesystem_limit
does not override the ancestor's
.Sy filesystem_limit ,
but rather imposes an additional limit.
This feature must be enabled to be used
.Po see
.Xr zpool-features 7
.Pc .
.It Sy mountpoint Ns = Ns Ar path | Cm none | legacy
Controls the mount point used for this file system. See the
.Qq Sx Mount Points
section for more information on how this property is used.
.Pp
When the
.Sy mountpoint
property is changed for a file system, the file system and any children that
inherit the mount point are unmounted. If the new value is
.Cm legacy ,
then they remain unmounted. Otherwise, they are automatically remounted in the
new location if the property was previously
.Cm legacy
or
.Cm none ,
or if they were mounted before the property was changed. In addition, any
shared file systems are unshared and shared in the new location.
.It Sy nbmand Ns = Ns Cm on | off
The
.Sy nbmand
property is currently not supported on
.Fx .
.It Sy primarycache Ns = Ns Cm all | none | metadata
Controls what is cached in the primary cache (ARC). If this property is set to
.Cm all ,
then both user data and metadata is cached. If this property is set to
.Cm none ,
then neither user data nor metadata is cached. If this property is set to
.Cm metadata ,
then only metadata is cached. The default value is
.Cm all .
.It Sy quota Ns = Ns Ar size | Cm none
Limits the amount of space a dataset and its descendents can consume. This
property enforces a hard limit on the amount of space used. This includes all
space consumed by descendents, including file systems and snapshots. Setting a
quota on a descendent of a dataset that already has a quota does not override
the ancestor's quota, but rather imposes an additional limit.
.Pp
Quotas cannot be set on volumes, as the
.Sy volsize
property acts as an implicit quota.
.It Sy snapshot_limit Ns = Ns Ar count | Cm none
Limits the number of snapshots that can be created on a dataset and its
descendents.
Setting a
.Sy snapshot_limit
on a descendent of a dataset that already
has a
.Sy snapshot_limit
does not override the ancestor's
.Sy snapshot_limit ,
but
rather imposes an additional limit.
The limit is not enforced if the user is
allowed to change the limit.
For example, this means that recursive snapshots
taken from the global zone are counted against each delegated dataset within
a jail.
This feature must be enabled to be used
.Po see
.Xr zpool-features 7
.Pc .
.It Sy userquota@ Ns Ar user Ns = Ns Ar size | Cm none
Limits the amount of space consumed by the specified user.
Similar to the
.Sy refquota
property, the
.Sy userquota
space calculation does not include space that is used by descendent datasets,
such as snapshots and clones. User space consumption is identified by the
.Sy userspace@ Ns Ar user
property.
.Pp
Enforcement of user quotas may be delayed by several seconds. This delay means
that a user might exceed their quota before the system notices that they are
over quota and begins to refuse additional writes with the
.Em EDQUOT
error message. See the
.Cm userspace
subcommand for more information.
.Pp
Unprivileged users can only access their own groups' space usage. The root
user, or a user who has been granted the
.Sy userquota
privilege with
.Qq Nm Cm allow ,
can get and set everyone's quota.
.Pp
This property is not available on volumes, on file systems before version 4, or
on pools before version 15. The
.Sy userquota@ Ns ...
properties are not displayed by
.Qq Nm Cm get all .
The user's name must be appended after the
.Sy @
symbol, using one of the following forms:
.Bl -bullet -offset 2n
.It
POSIX name (for example,
.Em joe )
.It
POSIX numeric ID (for example,
.Em 1001 )
.El
.It Sy groupquota@ Ns Ar group Ns = Ns Ar size | Cm none
Limits the amount of space consumed by the specified group. Group space
consumption is identified by the
.Sy userquota@ Ns Ar user
property.
.Pp
Unprivileged users can access only their own groups' space usage. The root
user, or a user who has been granted the
.Sy groupquota
privilege with
.Qq Nm Cm allow ,
can get and set all groups' quotas.
.It Sy readonly Ns = Ns Cm on | off
Controls whether this dataset can be modified. The default value is
.Cm off .
.It Sy recordsize Ns = Ns Ar size
Specifies a suggested block size for files in the file system. This property is
designed solely for use with database workloads that access files in fixed-size
records.
.Tn ZFS
automatically tunes block sizes according to internal algorithms optimized for
typical access patterns.
.Pp
For databases that create very large files but access them in small random
chunks, these algorithms may be suboptimal. Specifying a
.Sy recordsize
greater than or equal to the record size of the database can result in
significant performance gains. Use of this property for general purpose file
systems is strongly discouraged, and may adversely affect performance.
.Pp
The size specified must be a power of two greater than or equal to 512 and less
than or equal to 128 Kbytes.
If the
.Sy large_blocks
feature is enabled on the pool, the size may be up to 1 Mbyte.
See
.Xr zpool-features 7
for details on ZFS feature flags.
.Pp
Changing the file system's
.Sy recordsize
affects only files created afterward; existing files are unaffected.
.Pp
This property can also be referred to by its shortened column name,
.Sy recsize .
.It Sy redundant_metadata Ns = Ns Cm all | most
Controls what types of metadata are stored redundantly.
ZFS stores an extra copy of metadata, so that if a single block is corrupted,
the amount of user data lost is limited.
This extra copy is in addition to any redundancy provided at the pool level
.Pq e.g. by mirroring or RAID-Z ,
and is in addition to an extra copy specified by the
.Sy copies
property
.Pq up to a total of 3 copies .
For example if the pool is mirrored,
.Cm copies Ns = Ns Ar 2 ,
and
.Cm redundant_metadata Ns = Ns Ar most ,
then ZFS
stores 6 copies of most metadata, and 4 copies of data and some
metadata.
.Pp
When set to
.Cm all ,
ZFS stores an extra copy of all metadata.
If a
single on-disk block is corrupt, at worst a single block of user data
.Po which is
.Cm recordsize
bytes long
can be lost.
.Pc
.Pp
When set to
.Cm most ,
ZFS stores an extra copy of most types of
metadata.
This can improve performance of random writes, because less
metadata must be written.
In practice, at worst about 100 blocks
.Po of
.Cm recordsize
bytes each
.Pc
of user data can be lost if a single
on-disk block is corrupt.
The exact behavior of which metadata blocks
are stored redundantly may change in future releases.
.Pp
The default value is
.Cm all .
.It Sy refquota Ns = Ns Ar size | Cm none
Limits the amount of space a dataset can consume. This property enforces a hard
limit on the amount of space used. This hard limit does not include space used
by descendents, including file systems and snapshots.
.It Sy refreservation Ns = Ns Ar size | Cm none
The minimum amount of space guaranteed to a dataset, not including its
descendents. When the amount of space used is below this value, the dataset is
treated as if it were taking up the amount of space specified by
.Sy refreservation .
The
.Sy refreservation
reservation is accounted for in the parent datasets' space used, and counts
against the parent datasets' quotas and reservations.
.Pp
If
.Sy refreservation
is set, a snapshot is only allowed if there is enough free pool space outside
of this reservation to accommodate the current number of "referenced" bytes in
the dataset.
.Pp
This property can also be referred to by its shortened column name,
.Sy refreserv .
.It Sy reservation Ns = Ns Ar size | Cm none
The minimum amount of space guaranteed to a dataset and its descendents. When
the amount of space used is below this value, the dataset is treated as if it
were taking up the amount of space specified by its reservation. Reservations
are accounted for in the parent datasets' space used, and count against the
parent datasets' quotas and reservations.
.Pp
This property can also be referred to by its shortened column name,
.Sy reserv .
.It Sy secondarycache Ns = Ns Cm all | none | metadata
Controls what is cached in the secondary cache (L2ARC). If this property is set
to
.Cm all ,
then both user data and metadata is cached. If this property is set to
.Cm none ,
then neither user data nor metadata is cached. If this property is set to
.Cm metadata ,
then only metadata is cached. The default value is
.Cm all .
.It Sy setuid Ns = Ns Cm on | off
Controls whether the
.No set- Ns Tn UID
bit is respected for the file system. The default value is
.Cm on .
.It Sy sharesmb Ns = Ns Cm on | off | Ar opts
The
.Sy sharesmb
property currently has no effect on
.Fx .
.It Sy sharenfs Ns = Ns Cm on | off | Ar opts
Controls whether the file system is shared via
.Tn NFS ,
and what options are used. A file system with a
.Sy sharenfs
property of
.Cm off
is managed the traditional way via
.Xr exports 5 .
Otherwise, the file system is automatically shared and unshared with the
.Qq Nm Cm share
and
.Qq Nm Cm unshare
commands. If the property is set to
.Cm on
no
.Tn NFS
export options are used. Otherwise,
.Tn NFS
export options are equivalent to the contents of this property. The export
options may be comma-separated. See
.Xr exports 5
for a list of valid options.
.Pp
When the
.Sy sharenfs
property is changed for a dataset, the
.Xr mountd 8
daemon is reloaded.
.It Sy logbias Ns = Ns Cm latency | throughput
Provide a hint to
.Tn ZFS
about handling of synchronous requests in this dataset.
If
.Sy logbias
is set to
.Cm latency
(the default),
.Tn ZFS
will use pool log devices (if configured) to handle the requests at low
latency. If
.Sy logbias
is set to
.Cm throughput ,
.Tn ZFS
will not use configured pool log devices.
.Tn ZFS
will instead optimize synchronous operations for global pool throughput and
efficient use of resources.
.It Sy snapdir Ns = Ns Cm hidden | visible
Controls whether the
.Pa \&.zfs
directory is hidden or visible in the root of the file system as discussed in
the
.Qq Sx Snapshots
section. The default value is
.Cm hidden .
.It Sy sync Ns = Ns Cm standard | always | disabled
Controls the behavior of synchronous requests (e.g.
.Xr fsync 2 ,
O_DSYNC). This property accepts the following values:
.Bl -tag -offset 4n -width 8n
.It Sy standard
This is the POSIX specified behavior of ensuring all synchronous requests are
written to stable storage and all devices are flushed to ensure data is not
cached by device controllers (this is the default).
.It Sy always
All file system transactions are written and flushed before their system calls
return. This has a large performance penalty.
.It Sy disabled
Disables synchronous requests. File system transactions are only committed to
stable storage periodically. This option will give the highest performance.
However, it is very dangerous as
.Tn ZFS
would be ignoring the synchronous transaction demands of applications such as
databases or
.Tn NFS .
Administrators should only use this option when the risks are understood.
.El
.It Sy volsize Ns = Ns Ar size
For volumes, specifies the logical size of the volume. By default, creating a
volume establishes a reservation of equal size. For storage pools with a
version number of 9 or higher, a
.Sy refreservation
is set instead. Any changes to
.Sy volsize
are reflected in an equivalent change to the reservation (or
.Sy refreservation ) .
The
.Sy volsize
can only be set to a multiple of
.Cm volblocksize ,
and cannot be zero.
.Pp
The reservation is kept equal to the volume's logical size to prevent
unexpected behavior for consumers. Without the reservation, the volume could
run out of space, resulting in undefined behavior or data corruption, depending
on how the volume is used. These effects can also occur when the volume size is
changed while it is in use (particularly when shrinking the size). Extreme care
should be used when adjusting the volume size.
.Pp
Though not recommended, a "sparse volume" (also known as "thin provisioning")
can be created by specifying the
.Fl s
option to the
.Qq Nm Cm create Fl V
command, or by changing the reservation after the volume has been created. A
"sparse volume" is a volume where the reservation is less then the volume size.
Consequently, writes to a sparse volume can fail with
.Sy ENOSPC
when the pool is low on space. For a sparse volume, changes to
.Sy volsize
are not reflected in the reservation.
.It Sy volmode Ns = Ns Cm default | geom | dev | none
This property specifies how volumes should be exposed to the OS.
Setting it to
.Sy geom
exposes volumes as
.Xr geom 4
providers, providing maximal functionality.
Setting it to
.Sy dev
exposes volumes only as cdev device in devfs.
Such volumes can be accessed only as raw disk device files, i.e. they
can not be partitioned, mounted, participate in RAIDs, etc, but they
are faster, and in some use scenarios with untrusted consumer, such as
NAS or VM storage, can be more safe.
Volumes with property set to
.Sy none
are not exposed outside ZFS, but can be snapshoted, cloned, replicated, etc,
that can be suitable for backup purposes.
Value
.Sy default
means that volumes exposition is controlled by system-wide sysctl/tunable
.Va vfs.zfs.vol.mode ,
where
.Sy geom ,
.Sy dev
and
.Sy none
are encoded as 1, 2 and 3 respectively.
The default values is
.Sy geom .
This property can be changed any time, but so far it is processed only
during volume creation and pool import.
.It Sy vscan Ns = Ns Cm off | on
The
.Sy vscan
property is currently not supported on
.Fx .
.It Sy xattr Ns = Ns Cm off | on
The
.Sy xattr
property is currently not supported on
.Fx .
.It Sy jailed Ns = Ns Cm off | on
Controls whether the dataset is managed from a jail. See the
.Qq Sx Jails
section for more information. The default value is
.Cm off .
.El
.Pp
The following three properties cannot be changed after the file system is
created, and therefore, should be set when the file system is created. If the
properties are not set with the
.Qq Nm Cm create
or
.Nm zpool Cm create
commands, these properties are inherited from the parent dataset. If the parent
dataset lacks these properties due to having been created prior to these
features being supported, the new file system will have the default values for
these properties.
.Bl -tag -width 4n
.It Sy casesensitivity Ns = Ns Cm sensitive | insensitive | mixed
Indicates whether the file name matching algorithm used by the file system
should be case-sensitive, case-insensitive, or allow a combination of both
styles of matching. The default value for the
.Sy casesensitivity
property is
.Cm sensitive .
Traditionally, UNIX and POSIX file systems have case-sensitive file names.
.Pp
The
.Cm mixed
value for the
.Sy casesensitivity
property indicates that the
file system can support requests for both case-sensitive and case-insensitive
matching behavior.
.It Sy normalization Ns = Ns Cm none | formC | formD | formKC | formKD
Indicates whether the file system should perform a
.Sy unicode
normalization of file names whenever two file names are compared, and which
normalization algorithm should be used. File names are always stored
unmodified, names are normalized as part of any comparison process. If this
property is set to a legal value other than
.Cm none ,
and the
.Sy utf8only
property was left unspecified, the
.Sy utf8only
property is automatically set to
.Cm on .
The default value of the
.Sy normalization
property is
.Cm none .
This property cannot be changed after the file system is created.
.It Sy utf8only Ns = Ns Cm on | off
Indicates whether the file system should reject file names that include
characters that are not present in the
.Sy UTF-8
character code set. If this property is explicitly set to
.Cm off ,
the normalization property must either not be explicitly set or be set to
.Cm none .
The default value for the
.Sy utf8only
property is
.Cm off .
This property cannot be changed after the file system is created.
.El
.Pp
The
.Sy casesensitivity , normalization , No and Sy utf8only
properties are also new permissions that can be assigned to non-privileged
users by using the
.Tn ZFS
delegated administration feature.
.Ss Temporary Mount Point Properties
When a file system is mounted, either through
.Xr mount 8
for legacy mounts or the
.Qq Nm Cm mount
command for normal file systems, its mount options are set according to its
properties. The correlation between properties and mount options is as follows:
.Bl -column -offset 4n "PROPERTY" "MOUNT OPTION"
.It "PROPERTY	MOUNT OPTION"
.It "atime	atime/noatime"
.It "exec	exec/noexec"
.It "readonly	ro/rw"
.It "setuid	suid/nosuid"
.El
.Pp
In addition, these options can be set on a per-mount basis using the
.Fl o
option, without affecting the property that is stored on disk. The values
specified on the command line override the values stored in the dataset. These
properties are reported as "temporary" by the
.Qq Nm Cm get
command. If the properties are changed while the dataset is mounted, the new
setting overrides any temporary settings.
.Ss User Properties
In addition to the standard native properties,
.Tn ZFS
supports arbitrary user properties. User properties have no effect on
.Tn ZFS
behavior, but applications or administrators can use them to annotate datasets
(file systems, volumes, and snapshots).
.Pp
User property names must contain a colon
.Pq Sy \&:
character to distinguish them from native properties. They may contain
lowercase letters, numbers, and the following punctuation characters: colon
.Pq Sy \&: ,
dash
.Pq Sy \&- ,
period
.Pq Sy \&.
and underscore
.Pq Sy \&_ .
The expected convention is that the property name is divided into two portions
such as
.Em module Ns Sy \&: Ns Em property ,
but this namespace is not enforced by
.Tn ZFS .
User property names can be at most 256 characters, and cannot begin with a dash
.Pq Sy \&- .
.Pp
When making programmatic use of user properties, it is strongly suggested to
use a reversed
.Tn DNS
domain name for the
.Ar module
component of property names to reduce the chance that two
independently-developed packages use the same property name for different
purposes. Property names beginning with
.Em com.sun
are reserved for use by Sun Microsystems.
.Pp
The values of user properties are arbitrary strings, are always inherited, and
are never validated. All of the commands that operate on properties
.Po
.Qq Nm Cm list ,
.Qq Nm Cm get ,
.Qq Nm Cm set
and so forth
.Pc
can be used to manipulate both native properties and user properties. Use the
.Qq Nm Cm inherit
command to clear a user property. If the property is not defined in any parent
dataset, it is removed entirely. Property values are limited to 1024
characters.
.Sh SUBCOMMANDS
All subcommands that modify state are logged persistently to the pool in their
original form.
.Bl -tag -width 2n
.It Xo
.Nm
.Op Fl \&?
.Xc
.Pp
Displays a help message.
.It Xo
.Nm
.Cm create
.Op Fl pu
.Oo Fl o Ar property Ns = Ns Ar value Oc Ns ...
.Ar filesystem
.Xc
.Pp
Creates a new
.Tn ZFS
file system. The file system is automatically mounted according to the
.Sy mountpoint
property inherited from the parent.
.Bl -tag -width indent
.It Fl p
Creates all the non-existing parent datasets. Datasets created in this manner
are automatically mounted according to the
.Sy mountpoint
property inherited from their parent. Any property specified on the command
line using the
.Fl o
option is ignored. If the target filesystem already exists, the operation
completes successfully.
.It Fl u
Newly created file system is not mounted.
.It Fl o Ar property Ns = Ns Ar value
Sets the specified property as if the command
.Qq Nm Cm set Ar property Ns = Ns Ar value
was invoked at the same time the dataset was created. Any editable
.Tn ZFS
property can also be set at creation time. Multiple
.Fl o
options can be specified. An error results if the same property is specified in
multiple
.Fl o
options.
.El
.It Xo
.Nm
.Cm create
.Op Fl ps
.Op Fl b Ar blocksize
.Oo Fl o Ar property Ns = Ns Ar value Oc Ns ...
.Fl V
.Ar size volume
.Xc
.Pp
Creates a volume of the given size. The volume is exported as a block device in
.Pa /dev/zvol/path ,
where
.Ar path
is the name of the volume in the
.Tn ZFS
namespace. The size represents the logical size as exported by the device. By
default, a reservation of equal size is created.
.Pp
.Ar size
is automatically rounded up to the nearest 128 Kbytes to ensure that
the volume has an integral number of blocks regardless of
.Ar blocksize .
.Bl -tag -width indent
.It Fl p
Creates all the non-existing parent datasets. Datasets created in this manner
are automatically mounted according to the
.Sy mountpoint
property inherited from their parent. Any property specified on the command
line using the
.Fl o
option is ignored. If the target filesystem already exists, the operation
completes successfully.
.It Fl s
Creates a sparse volume with no reservation. See
.Sy volsize
in the
.Qq Sx Native Properties
section for more information about sparse volumes.
.It Fl b Ar blocksize
Equivalent to
.Fl o Cm volblocksize Ns = Ns Ar blocksize .
If this option is specified in conjunction with
.Fl o Cm volblocksize ,
the resulting behavior is undefined.
.It Fl o Ar property Ns = Ns Ar value
Sets the specified property as if the
.Qq Nm Cm set Ar property Ns = Ns Ar value
command was invoked at the same time the dataset was created. Any editable
.Tn ZFS
property can also be set at creation time. Multiple
.Fl o
options can be specified. An error results if the same property is specified in
multiple
.Fl o
options.
.El
.It Xo
.Nm
.Cm destroy
.Op Fl fnpRrv
.Ar filesystem Ns | Ns Ar volume
.Xc
.Pp
Destroys the given dataset. By default, the command unshares any file systems
that are currently shared, unmounts any file systems that are currently
mounted, and refuses to destroy a dataset that has active dependents (children
or clones).
.Bl -tag -width indent
.It Fl r
Recursively destroy all children.
.It Fl R
Recursively destroy all dependents, including cloned file systems outside the
target hierarchy.
.It Fl f
Force an unmount of any file systems using the
.Qq Nm Cm unmount Fl f
command. This option has no effect on non-file systems or unmounted file
systems.
.It Fl n
Do a dry-run ("No-op") deletion. No data will be deleted. This is useful in
conjunction with the
.Fl v
or
.Fl p
flags to determine what data would be deleted.
.It Fl p
Print machine-parsable verbose information about the deleted data.
.It Fl v
Print verbose information about the deleted data.
.El
.Pp
Extreme care should be taken when applying either the
.Fl r
or the
.Fl R
options, as they can destroy large portions of a pool and cause unexpected
behavior for mounted file systems in use.
.It Xo
.Nm
.Cm destroy
.Op Fl dnpRrv
.Sm off
.Ar snapshot
.Op % Ns Ar snapname
.Op , Ns ...
.Sm on
.Xc
.Pp
The given snapshots are destroyed immediately if and only if the
.Qq Nm Cm destroy
command without the
.Fl d
option would have destroyed it. Such immediate destruction would occur, for
example, if the snapshot had no clones and the user-initiated reference count
were zero.
.Pp
If a snapshot does not qualify for immediate destruction, it is marked for
deferred deletion. In this state, it exists as a usable, visible snapshot until
both of the preconditions listed above are met, at which point it is destroyed.
.Pp
An inclusive range of snapshots may be specified by separating the
first and last snapshots with a percent sign
.Pq Sy % .
The first and/or last snapshots may be left blank, in which case the
filesystem's oldest or newest snapshot will be implied.
.Pp
Multiple snapshots
(or ranges of snapshots) of the same filesystem or volume may be specified
in a comma-separated list of snapshots.
Only the snapshot's short name (the
part after the
.Sy @ )
should be specified when using a range or comma-separated list to identify
multiple snapshots.
.Bl -tag -width indent
.It Fl r
Destroy (or mark for deferred deletion) all snapshots with this name in
descendent file systems.
.It Fl R
Recursively destroy all clones of these snapshots, including the clones,
snapshots, and children.
If this flag is specified, the
.Fl d
flag will have no effect.
.It Fl n
Do a dry-run ("No-op") deletion. No data will be deleted. This is useful in
conjunction with the
.Fl v
or
.Fl p
flags to determine what data would be deleted.
.It Fl p
Print machine-parsable verbose information about the deleted data.
.It Fl v
Print verbose information about the deleted data.
.It Fl d
Defer snapshot deletion.
.El
.Pp
Extreme care should be taken when applying either the
.Fl r
or the
.Fl R
options, as they can destroy large portions of a pool and cause unexpected
behavior for mounted file systems in use.
.It Xo
.Nm
.Cm destroy
.Ar filesystem Ns | Ns Ar volume Ns # Ns Ar bookmark
.Xc
.Pp
The given bookmark is destroyed.
.It Xo
.Nm
.Cm snapshot Ns | Ns Cm snap
.Op Fl r
.Oo Fl o Ar property Ns = Ns Ar value Oc Ns ...
.Ar filesystem@snapname Ns | Ns volume@snapname
.Ar filesystem@snapname Ns | Ns volume@snapname Ns ...
.Xc
.Pp
Creates snapshots with the given names. All previous modifications by
successful system calls to the file system are part of the snapshots.
Snapshots are taken atomically, so that all snapshots correspond to the same
moment in time. See the
.Qq Sx Snapshots
section for details.
.Bl -tag -width indent
.It Fl r
Recursively create snapshots of all descendent datasets
.It Fl o Ar property Ns = Ns Ar value
Sets the specified property; see
.Qq Nm Cm create
for details.
.El
.It Xo
.Nm
.Cm rollback
.Op Fl rRf
.Ar snapshot
.Xc
.Pp
Roll back the given dataset to a previous snapshot. When a dataset is rolled
back, all data that has changed since the snapshot is discarded, and the
dataset reverts to the state at the time of the snapshot. By default, the
command refuses to roll back to a snapshot other than the most recent one. In
order to do so, all intermediate snapshots and bookmarks must be destroyed
by specifying the
.Fl r
option.
.Pp
The
.Fl rR
options do not recursively destroy the child snapshots of a
recursive snapshot.
Only direct snapshots of the specified filesystem
are destroyed by either of these options.
To completely roll back a
recursive snapshot, you must rollback the individual child snapshots.
.Bl -tag -width indent
.It Fl r
Destroy any snapshots and bookmarks more recent than the one specified.
.It Fl R
Destroy any more recent snapshots and bookmarks, as well as any clones of those
snapshots.
.It Fl f
Used with the
.Fl R
option to force an unmount of any clone file systems that are to be destroyed.
.El
.It Xo
.Nm
.Cm clone
.Op Fl p
.Oo Fl o Ar property Ns = Ns Ar value Oc Ns ...
.Ar snapshot filesystem Ns | Ns Ar volume
.Xc
.Pp
Creates a clone of the given snapshot. See the
.Qq Sx Clones
section for details. The target dataset can be located anywhere in the
.Tn ZFS
hierarchy, and is created as the same type as the original.
.Bl -tag -width indent
.It Fl p
Creates all the non-existing parent datasets. Datasets created in this manner
are automatically mounted according to the
.Sy mountpoint
property inherited from their parent. If the target filesystem or volume
already exists, the operation completes successfully.
.It Fl o Ar property Ns = Ns Ar value
Sets the specified property; see
.Qq Nm Cm create
for details.
.El
.It Xo
.Nm
.Cm promote
.Ar clone-filesystem
.Xc
.Pp
Promotes a clone file system to no longer be dependent on its "origin"
snapshot. This makes it possible to destroy the file system that the clone was
created from. The clone parent-child dependency relationship is reversed, so
that the origin file system becomes a clone of the specified file system.
.Pp
The snapshot that was cloned, and any snapshots previous to this snapshot, are
now owned by the promoted clone. The space they use moves from the origin file
system to the promoted clone, so enough space must be available to accommodate
these snapshots. No new space is consumed by this operation, but the space
accounting is adjusted. The promoted clone must not have any conflicting
snapshot names of its own. The
.Cm rename
subcommand can be used to rename any conflicting snapshots.
.It Xo
.Nm
.Cm rename
.Op Fl f
.Ar filesystem Ns | Ns Ar volume Ns | Ns Ar snapshot
.Ar filesystem Ns | Ns Ar volume Ns | Ns Ar snapshot
.Xc
.It Xo
.Nm
.Cm rename
.Op Fl f
.Fl p
.Ar filesystem Ns | Ns Ar volume
.Ar filesystem Ns | Ns Ar volume
.Xc
.It Xo
.Nm
.Cm rename
.Fl u
.Op Fl p
.Ar filesystem filesystem
.Xc
.Pp
Renames the given dataset. The new target can be located anywhere in the
.Tn ZFS
hierarchy, with the exception of snapshots. Snapshots can only be renamed
within the parent file system or volume. When renaming a snapshot, the parent
file system of the snapshot does not need to be specified as part of the second
argument. Renamed file systems can inherit new mount points, in which case they
are unmounted and remounted at the new mount point.
.Bl -tag -width indent
.It Fl p
Creates all the nonexistent parent datasets. Datasets created in this manner
are automatically mounted according to the
.Sy mountpoint
property inherited from their parent.
.It Fl u
Do not remount file systems during rename. If a file system's
.Sy mountpoint
property is set to
.Cm legacy
or
.Cm none ,
file system is not unmounted even if this option is not given.
.It Fl f
Force unmount any filesystems that need to be unmounted in the process.
This flag has no effect if used together with the
.Fl u
flag.
.El
.It Xo
.Nm
.Cm rename
.Fl r
.Ar snapshot snapshot
.Xc
.Pp
Recursively rename the snapshots of all descendent datasets. Snapshots are the
only dataset that can be renamed recursively.
.It Xo
.Nm
.Cm list
.Op Fl r Ns | Ns Fl d Ar depth
.Op Fl Hp
.Op Fl o Ar property Ns Oo , Ns Ar property Oc Ns ...
.Op Fl t Ar type Ns Oo , Ns Ar type Oc Ns ...
.Oo Fl s Ar property Oc Ns ...
.Oo Fl S Ar property Oc Ns ...
.Ar filesystem Ns | Ns Ar volume Ns | Ns Ar snapshot Ns ...
.Xc
.Pp
Lists the property information for the given datasets in tabular form. If
specified, you can list property information by the absolute pathname or the
relative pathname. By default, all file systems and volumes are displayed.
Snapshots are displayed if the
.Sy listsnaps
property is
.Cm on
(the default is
.Cm off ) .
The following fields are displayed,
.Sy name , used , available , referenced , mountpoint .
.Bl -tag -width indent
.It Fl r
Recursively display any children of the dataset on the command line.
.It Fl d Ar depth
Recursively display any children of the dataset, limiting the recursion to
.Ar depth .
A depth of
.Sy 1
will display only the dataset and its direct children.
.It Fl H
Used for scripting mode. Do not print headers and separate fields by a single
tab instead of arbitrary white space.
.It Fl p
Display numbers in parsable (exact) values.
.It Fl o Ar property Ns Oo , Ns Ar property Oc Ns ...
A comma-separated list of properties to display. The property must be:
.Bl -bullet -offset 2n
.It
One of the properties described in the
.Qq Sx Native Properties
section
.It
A user property
.It
The value
.Cm name
to display the dataset name
.It
The value
.Cm space
to display space usage properties on file systems and volumes. This is a
shortcut for specifying
.Fl o
.Sy name,avail,used,usedsnap,usedds,usedrefreserv,usedchild
.Fl t
.Sy filesystem,volume
syntax.
.El
.It Fl t Ar type Ns Oo , Ns Ar type Oc Ns ...
A comma-separated list of types to display, where
.Ar type
is one of
.Sy filesystem , snapshot , snap , volume , bookmark , No or Sy all .
For example, specifying
.Fl t Cm snapshot
displays only snapshots.
.It Fl s Ar property
A property for sorting the output by column in ascending order based on the
value of the property. The property must be one of the properties described in
the
.Qq Sx Properties
section, or the special value
.Cm name
to sort by the dataset name. Multiple properties can be specified at one time
using multiple
.Fl s
property options. Multiple
.Fl s
options are evaluated from left to right in decreasing order of importance.
.Pp
The following is a list of sorting criteria:
.Bl -bullet -offset 2n
.It
Numeric types sort in numeric order.
.It
String types sort in alphabetical order.
.It
Types inappropriate for a row sort that row to the literal bottom, regardless
of the specified ordering.
.It
If no sorting options are specified the existing behavior of
.Qq Nm Cm list
is preserved.
.El
.It Fl S Ar property
Same as the
.Fl s
option, but sorts by property in descending order.
.El
.It Xo
.Nm
.Cm set
.Ar property Ns = Ns Ar value
.Ar filesystem Ns | Ns Ar volume Ns | Ns Ar snapshot
.Xc
.Pp
Sets the property to the given value for each dataset. Only some properties can
be edited. See the "Properties" section for more information on what properties
can be set and acceptable values. Numeric values can be specified as exact
values, or in a human-readable form with a suffix of
.Sy B , K , M , G , T , P , E , Z
(for bytes, kilobytes, megabytes, gigabytes, terabytes, petabytes, exabytes, or
zettabytes, respectively). User properties can be set on snapshots. For more
information, see the
.Qq Sx User Properties
section.
.It Xo
.Nm
.Cm get
.Op Fl r Ns | Ns Fl d Ar depth
.Op Fl Hp
.Op Fl o Ar all | field Ns Oo , Ns Ar field Oc Ns ...
.Op Fl t Ar type Ns Oo , Ns Ar type Oc Ns ...
.Op Fl s Ar source Ns Oo , Ns Ar source Oc Ns ...
.Ar all | property Ns Oo , Ns Ar property Oc Ns ...
.Ar filesystem Ns | Ns Ar volume Ns | Ns Ar snapshot Ns ...
.Xc
.Pp
Displays properties for the given datasets. If no datasets are specified, then
the command displays properties for all datasets on the system. For each
property, the following columns are displayed:
.Pp
.Bl -hang -width "property" -offset indent -compact
.It name
Dataset name
.It property
Property name
.It value
Property value
.It source
Property source. Can either be local, default, temporary, inherited, or none
(\&-).
.El
.Pp
All columns except the
.Sy RECEIVED
column are displayed by default. The columns to display can be specified
by using the
.Fl o
option. This command takes a comma-separated list of properties as described in
the
.Qq Sx Native Properties
and
.Qq Sx User Properties
sections.
.Pp
The special value
.Cm all
can be used to display all properties that apply to the given dataset's type
(filesystem, volume, snapshot, or bookmark).
.Bl -tag -width indent
.It Fl r
Recursively display properties for any children.
.It Fl d Ar depth
Recursively display any children of the dataset, limiting the recursion to
.Ar depth .
A depth of
.Sy 1
will display only the dataset and its direct children.
.It Fl H
Display output in a form more easily parsed by scripts. Any headers are
omitted, and fields are explicitly separated by a single tab instead of an
arbitrary amount of space.
.It Fl p
Display numbers in parsable (exact) values.
.It Fl o Cm all | Ar field Ns Oo , Ns Ar field Oc Ns ...
A comma-separated list of columns to display. Supported values are
.Sy name,property,value,received,source .
Default values are
.Sy name,property,value,source .
The keyword
.Cm all
specifies all columns.
.It Fl t Ar type Ns Oo , Ns Ar type Oc Ns ...
A comma-separated list of types to display, where
.Ar type
is one of
.Sy filesystem , snapshot , volume , No or Sy all .
For example, specifying
.Fl t Cm snapshot
displays only snapshots.
.It Fl s Ar source Ns Oo , Ns Ar source Oc Ns ...
A comma-separated list of sources to display. Those properties coming from a
source other than those in this list are ignored. Each source must be one of
the following:
.Sy local,default,inherited,temporary,received,none .
The default value is all sources.
.El
.It Xo
.Nm
.Cm inherit
.Op Fl rS
.Ar property
.Ar filesystem Ns | Ns Ar volume Ns | Ns Ar snapshot Ns ...
.Xc
.Pp
Clears the specified property, causing it to be inherited from an ancestor. If
no ancestor has the property set, then the default value is used. See the
.Qq Sx Properties
section for a listing of default values, and details on which properties can be
inherited.
.Bl -tag -width indent
.It Fl r
Recursively inherit the given property for all children.
.It Fl S
For properties with a received value, revert to this value. This flag has no
effect on properties that do not have a received value.
.El
.It Xo
.Nm
.Cm upgrade
.Op Fl v
.Xc
.Pp
Displays a list of file systems that are not the most recent version.
.Bl -tag -width indent
.It Fl v
Displays
.Tn ZFS
filesystem versions supported by the current software. The current
.Tn ZFS
filesystem version and all previous supported versions are displayed, along
with an explanation of the features provided with each version.
.El
.It Xo
.Nm
.Cm upgrade
.Op Fl r
.Op Fl V Ar version
.Fl a | Ar filesystem
.Xc
.Pp
Upgrades file systems to a new on-disk version. Once this is done, the file
systems will no longer be accessible on systems running older versions of the
software.
.Qq Nm Cm send
streams generated from new snapshots of these file systems cannot be accessed
on systems running older versions of the software.
.Pp
In general, the file system version is independent of the pool version. See
.Xr zpool 8
for information on the
.Nm zpool Cm upgrade
command.
.Pp
In some cases, the file system version and the pool version are interrelated
and the pool version must be upgraded before the file system version can be
upgraded.
.Bl -tag -width indent
.It Fl r
Upgrade the specified file system and all descendent file systems.
.It Fl V Ar version
Upgrade to the specified
.Ar version .
If the
.Fl V
flag is not specified, this command upgrades to the most recent version. This
option can only be used to increase the version number, and only up to the most
recent version supported by this software.
.It Fl a
Upgrade all file systems on all imported pools.
.It Ar filesystem
Upgrade the specified file system.
.El
.It Xo
.Nm
.Cm userspace
.Op Fl Hinp
.Op Fl o Ar field Ns Oo , Ns Ar field Oc Ns ...
.Oo Fl s Ar field Oc Ns ...
.Oo Fl S Ar field Oc Ns ...
.Op Fl t Ar type Ns Oo , Ns Ar type Oc Ns ...
.Ar filesystem Ns | Ns Ar snapshot
.Xc
.Pp
Displays space consumed by, and quotas on, each user in the specified
filesystem or snapshot. This corresponds to the
.Sy userused@ Ns Ar user
and
.Sy userquota@ Ns Ar user
properties.
.Bl -tag -width indent
.It Fl n
Print numeric ID instead of user/group name.
.It Fl H
Do not print headers, use tab-delimited output.
.It Fl p
Use exact (parsable) numeric output.
.It Fl o Ar field Ns Oo , Ns Ar field Oc Ns ...
Display only the specified fields from the following set:
.Sy type,name,used,quota .
The default is to display all fields.
.It Fl s Ar field
Sort output by this field. The
.Fl s
and
.Fl S
flags may be specified multiple times to sort first by one field, then by
another. The default is
.Fl s Cm type Fl s Cm name .
.It Fl S Ar field
Sort by this field in reverse order. See
.Fl s .
.It Fl t Ar type Ns Oo , Ns Ar type Oc Ns ...
Print only the specified types from the following set:
.Sy all,posixuser,smbuser,posixgroup,smbgroup .
.Pp
The default is
.Fl t Cm posixuser,smbuser .
.Pp
The default can be changed to include group types.
.It Fl i
Translate SID to POSIX ID. This flag currently has no effect on
.Fx .
.El
.It Xo
.Nm
.Cm groupspace
.Op Fl Hinp
.Op Fl o Ar field Ns Oo , Ns Ar field Oc Ns ...
.Oo Fl s Ar field Oc Ns ...
.Oo Fl S Ar field Oc Ns ...
.Op Fl t Ar type Ns Oo , Ns Ar type Oc Ns ...
.Ar filesystem Ns | Ns Ar snapshot
.Xc
.Pp
Displays space consumed by, and quotas on, each group in the specified
filesystem or snapshot. This subcommand is identical to
.Qq Nm Cm userspace ,
except that the default types to display are
.Fl t Sy posixgroup,smbgroup .
.It Xo
.Nm
.Cm mount
.Xc
.Pp
Displays all
.Tn ZFS
file systems currently mounted.
.Bl -tag -width indent
.It Fl f
.El
.It Xo
.Nm
.Cm mount
.Op Fl vO
.Op Fl o Ar property Ns Oo , Ns Ar property Oc Ns ...
.Fl a | Ar filesystem
.Xc
.Pp
Mounts
.Tn ZFS
file systems.
.Bl -tag -width indent
.It Fl v
Report mount progress.
.It Fl O
Perform an overlay mount. Overlay mounts are not supported on
.Fx .
.It Fl o Ar property Ns Oo , Ns Ar property Oc Ns ...
An optional, comma-separated list of mount options to use temporarily for the
duration of the mount. See the
.Qq Sx Temporary Mount Point Properties
section for details.
.It Fl a
Mount all available
.Tn ZFS
file systems.
This command may be executed on
.Fx
system startup by
.Pa /etc/rc.d/zfs .
For more information, see variable
.Va zfs_enable
in
.Xr rc.conf 5 .
.It Ar filesystem
Mount the specified filesystem.
.El
.It Xo
.Nm
.Cm unmount Ns | Ns Cm umount
.Op Fl f
.Fl a | Ar filesystem Ns | Ns Ar mountpoint
.Xc
.Pp
Unmounts currently mounted
.Tn ZFS
file systems.
.Bl -tag -width indent
.It Fl f
Forcefully unmount the file system, even if it is currently in use.
.It Fl a
Unmount all available
.Tn ZFS
file systems.
.It Ar filesystem | mountpoint
Unmount the specified filesystem. The command can also be given a path to a
.Tn ZFS
file system mount point on the system.
.El
.It Xo
.Nm
.Cm share
.Fl a | Ar filesystem
.Xc
.Pp
Shares
.Tn ZFS
file systems that have the
.Sy sharenfs
property set.
.Bl -tag -width indent
.It Fl a
Share all
.Tn ZFS
file systems that have the
.Sy sharenfs
property set.
This command may be executed on
.Fx
system startup by
.Pa /etc/rc.d/zfs .
For more information, see variable
.Va zfs_enable
in
.Xr rc.conf 5 .
.It Ar filesystem
Share the specified filesystem according to the
.Tn sharenfs
property. File systems are shared when the
.Tn sharenfs
property is set.
.El
.It Xo
.Nm
.Cm unshare
.Fl a | Ar filesystem Ns | Ns Ar mountpoint
.Xc
.Pp
Unshares
.Tn ZFS
file systems that have the
.Tn sharenfs
property set.
.Bl -tag -width indent
.It Fl a
Unshares
.Tn ZFS
file systems that have the
.Sy sharenfs
property set.
This command may be executed on
.Fx
system shutdown by
.Pa /etc/rc.d/zfs .
For more information, see variable
.Va zfs_enable
in
.Xr rc.conf 5 .
.It Ar filesystem | mountpoint
Unshare the specified filesystem. The command can also be given a path to a
.Tn ZFS
file system shared on the system.
.El
.It Xo
.Nm
.Cm bookmark
.Ar snapshot
.Ar bookmark
.Xc
.Pp
Creates a bookmark of the given snapshot.
Bookmarks mark the point in time
when the snapshot was created, and can be used as the incremental source for
a
.Qq Nm Cm send
command.
.Pp
This feature must be enabled to be used.
See
.Xr zpool-features 7
for details on ZFS feature flags and the
.Sy bookmark
feature.
.It Xo
.Nm
.Cm send
.Op Fl DnPpRveL
.Op Fl i Ar snapshot | Fl I Ar snapshot
.Ar snapshot
.Xc
.Pp
Creates a stream representation of the last
.Ar snapshot
argument (not part of
.Fl i
or
.Fl I )
which is written to standard output. The output can be redirected to
a file or to a different system (for example, using
.Xr ssh 1 ) .
By default, a full stream is generated.
.Bl -tag -width indent
.It Fl i Ar snapshot
Generate an incremental stream from the first
.Ar snapshot Pq the incremental source
to the second
.Ar snapshot Pq the incremental target .
The incremental source can be specified as the last component of the
snapshot name
.Pq the Em @ No character and following
and
it is assumed to be from the same file system as the incremental target.
.Pp
If the destination is a clone, the source may be the origin snapshot, which
must be fully specified (for example,
.Cm pool/fs@origin ,
not just
.Cm @origin ) .
.It Fl I Ar snapshot
Generate a stream package that sends all intermediary snapshots from the first
.Ar snapshot
to the second
.Ar snapshot .
For example,
.Ic -I @a fs@d
is similar to
.Ic -i @a fs@b; -i @b fs@c; -i @c fs@d .
The incremental
source may be specified as with the
.Fl i
option.
.It Fl R
Generate a replication stream package, which will replicate the specified
filesystem, and all descendent file systems, up to the named snapshot. When
received, all properties, snapshots, descendent file systems, and clones are
preserved.
.Pp
If the
.Fl i
or
.Fl I
flags are used in conjunction with the
.Fl R
flag, an incremental replication stream is generated. The current values of
properties, and current snapshot and file system names are set when the stream
is received. If the
.Fl F
flag is specified when this stream is received, snapshots and file systems that
do not exist on the sending side are destroyed.
.It Fl D
Generate a deduplicated stream. Blocks which would have been sent multiple
times in the send stream will only be sent once.  The receiving system must
also support this feature to receive a deduplicated stream.  This flag can
be used regardless of the dataset's
.Sy dedup
property, but performance will be much better if the filesystem uses a
dedup-capable checksum (eg.
.Sy sha256 ) .
.It Fl L
Generate a stream which may contain blocks larger than 128KB.
This flag
has no effect if the
.Sy large_blocks
pool feature is disabled, or if the
.Sy recordsize
property of this filesystem has never been set above 128KB.
The receiving system must have the
.Sy large_blocks
pool feature enabled as well.
See
.Xr zpool-features 7
for details on ZFS feature flags and the
.Sy large_blocks
feature.
.It Fl e
Generate a more compact stream by using WRITE_EMBEDDED records for blocks
which are stored more compactly on disk by the
.Sy embedded_data
pool
feature.
This flag has no effect if the
.Sy embedded_data
feature is
disabled.
The receiving system must have the
.Sy embedded_data
feature
enabled.
If the
.Sy lz4_compress
feature is active on the sending system,
then the receiving system must have that feature enabled as well.
See
.Xr zpool-features 7
for details on ZFS feature flags and the
.Sy embedded_data
feature.
.It Fl p
Include the dataset's properties in the stream. This flag is implicit when
.Fl R
is specified. The receiving system must also support this feature.
.It Fl n
Do a dry-run ("No-op") send.  Do not generate any actual send data.  This is
useful in conjunction with the
.Fl v
or
.Fl P
flags to determine what data will be sent.
.It Fl P
Print machine-parsable verbose information about the stream package generated.
.It Fl v
Print verbose information about the stream package generated.
This information includes a per-second report of how much data has been sent.
.El
.Pp
The format of the stream is committed. You will be able to receive your streams
on future versions of
.Tn ZFS .
.It Xo
.Nm
.Cm send
.Op Fl eL
.Op Fl i Ar snapshot Ns | Ns Ar bookmark
.Ar filesystem Ns | Ns Ar volume Ns | Ns Ar snapshot
.Xc
.Pp
Generate a send stream, which may be of a filesystem, and may be
incremental from a bookmark.
If the destination is a filesystem or volume,
the pool must be read-only, or the filesystem must not be mounted.
When the
stream generated from a filesystem or volume is received, the default snapshot
name will be
.Pq --head-- .
.Bl -tag -width indent
.It Fl i Ar snapshot Ns | Ns bookmark
Generate an incremental send stream.
The incremental source must be an earlier
snapshot in the destination's history.
It will commonly be an earlier
snapshot in the destination's filesystem, in which case it can be
specified as the last component of the name
.Pq the Em # No or Em @ No character and following .
.Pp
If the incremental target is a clone, the incremental source can
be the origin snapshot, or an earlier snapshot in the origin's filesystem,
or the origin's origin, etc.
.It Fl L
Generate a stream which may contain blocks larger than 128KB.
This flag
has no effect if the
.Sy large_blocks
pool feature is disabled, or if the
.Sy recordsize
property of this filesystem has never been set above 128KB.
The receiving system must have the
.Sy large_blocks
pool feature enabled as well.
See
.Xr zpool-features 7
for details on ZFS feature flags and the
.Sy large_blocks
feature.
.It Fl e
Generate a more compact stream by using WRITE_EMBEDDED records for blocks
which are stored more compactly on disk by the
.Sy embedded_data
pool
feature.
This flag has no effect if the
.Sy embedded_data
feature is
disabled.
The receiving system must have the
.Sy embedded_data
feature
enabled.
If the
.Sy lz4_compress
feature is active on the sending system,
then the receiving system must have that feature enabled as well.
See
.Xr zpool-features 7
for details on ZFS feature flags and the
.Sy embedded_data
feature.
.El
.It Xo
.Nm
.Cm receive Ns | Ns Cm recv
.Op Fl vnFu
.Ar filesystem Ns | Ns Ar volume Ns | Ns Ar snapshot
.Xc
.It Xo
.Nm
.Cm receive Ns | Ns Cm recv
.Op Fl vnFu
.Op Fl d | e
.Ar filesystem
.Xc
.Pp
Creates a snapshot whose contents are as specified in the stream provided on
standard input. If a full stream is received, then a new file system is created
as well. Streams are created using the
.Qq Nm Cm send
subcommand, which by default creates a full stream.
.Qq Nm Cm recv
can be used as an alias for
.Qq Nm Cm receive .
.Pp
If an incremental stream is received, then the destination file system must
already exist, and its most recent snapshot must match the incremental stream's
source. For
.Sy zvol Ns s,
the destination device link is destroyed and recreated, which means the
.Sy zvol
cannot be accessed during the
.Sy receive
operation.
.Pp
When a snapshot replication package stream that is generated by using the
.Qq Nm Cm send Fl R
command is received, any snapshots that do not exist on the sending location
are destroyed by using the
.Qq Nm Cm destroy Fl d
command.
.Pp
The name of the snapshot (and file system, if a full stream is received) that
this subcommand creates depends on the argument type and the
.Fl d
or
.Fl e
option.
.Pp
If the argument is a snapshot name, the specified
.Ar snapshot
is created. If the argument is a file system or volume name, a snapshot with
the same name as the sent snapshot is created within the specified
.Ar filesystem
or
.Ar volume .
If the
.Fl d
or
.Fl e
option is specified, the snapshot name is determined by appending the sent
snapshot's name to the specified
.Ar filesystem .
If the
.Fl d
option is specified, all but the pool name of the sent snapshot path is
appended (for example,
.Sy b/c@1
appended from sent snapshot
.Sy a/b/c@1 ) ,
and if the
.Fl e
option is specified, only the tail of the sent snapshot path is appended (for
example,
.Sy c@1
appended from sent snapshot
.Sy a/b/c@1 ) .
In the case of
.Fl d ,
any file systems needed to replicate the path of the sent snapshot are created
within the specified file system.
.Bl -tag -width indent
.It Fl d
Use the full sent snapshot path without the first element (without pool name)
to determine the name of the new snapshot as described in the paragraph above.
.It Fl e
Use only the last element of the sent snapshot path to determine the name of
the new snapshot as described in the paragraph above.
.It Fl u
File system that is associated with the received stream is not mounted.
.It Fl v
Print verbose information about the stream and the time required to perform the
receive operation.
.It Fl n
Do not actually receive the stream. This can be useful in conjunction with the
.Fl v
option to verify the name the receive operation would use.
.It Fl F
Force a rollback of the file system to the most recent snapshot before
performing the receive operation. If receiving an incremental replication
stream (for example, one generated by
.Qq Nm Cm send Fl R Bro Fl i | Fl I Brc ) ,
destroy snapshots and file systems that do not exist on the sending side.
.El
.It Xo
.Nm
.Cm allow
.Ar filesystem Ns | Ns Ar volume
.Xc
.Pp
Displays permissions that have been delegated on the specified filesystem or
volume. See the other forms of
.Qq Nm Cm allow
for more information.
.It Xo
.Nm
.Cm allow
.Op Fl ldug
.Ar user Ns | Ns Ar group Ns Oo Ns , Ns Ar user Ns | Ns Ar group Oc Ns ...
.Ar perm Ns | Ns Ar @setname Ns
.Oo Ns , Ns Ar perm Ns | Ns Ar @setname Oc Ns ...
.Ar filesystem Ns | Ns Ar volume
.Xc
.It Xo
.Nm
.Cm allow
.Op Fl ld
.Fl e Ns | Ns Cm everyone
.Ar perm Ns | Ns Ar @setname Ns Op Ns , Ns Ar perm Ns | Ns Ar @setname Ns
.Ns ...
.Ar filesystem Ns | Ns Ar volume
.Xc
.Pp
Delegates
.Tn ZFS
administration permission for the file systems to non-privileged users.
.Bl -tag -width indent
.It Xo
.Op Fl ug
.Ar user Ns | Ns Ar group Ns Oo , Ar user Ns | Ns Ar group Oc Ns ...
.Xc
Specifies to whom the permissions are delegated. Multiple entities can be
specified as a comma-separated list. If neither of the
.Fl ug
options are specified, then the argument is interpreted preferentially as the
keyword
.Cm everyone ,
then as a user name, and lastly as a group name. To specify
a user or group named
.Qq everyone ,
use the
.Fl u
or
.Fl g
options. To specify a group with the same name as a user, use the
.Fl g
option.
.It Op Fl e Ns | Ns Cm everyone
Specifies that the permissions be delegated to
.Qq everyone .
.It Xo
.Ar perm Ns | Ns Ar @setname Ns Oo , Ns Ar perm Ns | Ns Ar @setname Oc Ns ...
.Xc
The permissions to delegate. Multiple permissions
may be specified as a comma-separated list. Permission names are the same as
.Tn ZFS
subcommand and property names. See the property list below. Property set names,
which begin with an at sign
.Pq Sy @ ,
may be specified. See the
.Fl s
form below for details.
.It Xo
.Op Fl ld
.Ar filesystem Ns | Ns Ar volume
.Xc
Specifies where the permissions are delegated. If neither of the
.Fl ld
options are specified, or both are, then the permissions are allowed for the
file system or volume, and all of its descendents. If only the
.Fl l
option is used, then is allowed "locally" only for the specified file system.
If only the
.Fl d
option is used, then is allowed only for the descendent file systems.
.El
.Pp
Permissions are generally the ability to use a
.Tn ZFS
subcommand or change a
.Tn ZFS
property. The following permissions are available:
.Bl -column -offset 4n "secondarycache" "subcommand"
.It NAME Ta TYPE Ta NOTES
.It allow Ta subcommand Ta Must Xo
also have the permission that is being allowed
.Xc
.It clone Ta subcommand Ta Must Xo
also have the 'create' ability and 'mount' ability in the origin file system
.Xc
.It create Ta subcommand Ta Must also have the 'mount' ability
.It destroy Ta subcommand Ta Must also have the 'mount' ability
.It diff Ta subcommand Ta Allows lookup of paths within a dataset given an
object number, and the ability to create snapshots necessary to 'zfs diff'
.It hold Ta subcommand Ta Allows adding a user hold to a snapshot
.It mount Ta subcommand Ta Allows mount/umount of Tn ZFS No datasets
.It promote Ta subcommand Ta Must Xo
also have the 'mount' and 'promote' ability in the origin file system
.Xc
.It receive Ta subcommand Ta Must also have the 'mount' and 'create' ability
.It release Ta subcommand Ta Allows Xo
releasing a user hold which might destroy the snapshot
.Xc
.It rename Ta subcommand Ta Must Xo
also have the 'mount' and 'create' ability in the new parent
.Xc
.It rollback Ta subcommand Ta Must also have the 'mount' ability
.It send Ta subcommand
.It share Ta subcommand Ta Allows Xo
sharing file systems over the
.Tn NFS
protocol
.Xc
.It snapshot Ta subcommand Ta Must also have the 'mount' ability
.It groupquota Ta other Ta Allows accessing any groupquota@... property
.It groupused Ta other Ta Allows reading any groupused@... property
.It userprop Ta other Ta Allows changing any user property
.It userquota Ta other Ta Allows accessing any userquota@... property
.It userused Ta other Ta Allows reading any userused@... property
.It aclinherit Ta property
.It aclmode Ta property
.It atime Ta property
.It canmount Ta property
.It casesensitivity Ta property
.It checksum Ta property
.It compression Ta property
.It copies Ta property
.It dedup Ta property
.It devices Ta property
.It exec Ta property
.It filesystem_limit Ta property
.It logbias Ta property
.It jailed Ta property
.It mlslabel Ta property
.It mountpoint Ta property
.It nbmand Ta property
.It normalization Ta property
.It primarycache Ta property
.It quota Ta property
.It readonly Ta property
.It recordsize Ta property
.It refquota Ta property
.It refreservation Ta property
.It reservation Ta property
.It secondarycache Ta property
.It setuid Ta property
.It sharenfs Ta property
.It sharesmb Ta property
.It snapdir Ta property
.It snapshot_limit Ta property
.It sync Ta property
.It utf8only Ta property
.It version Ta property
.It volblocksize Ta property
.It volsize Ta property
.It vscan Ta property
.It xattr Ta property
.El
.It Xo
.Nm
.Cm allow
.Fl c
.Ar perm Ns | Ns Ar @setname Ns Op Ns , Ns Ar perm Ns | Ns Ar @setname Ns
.Ns ...
.Ar filesystem Ns | Ns Ar volume
.Xc
.Pp
Sets "create time" permissions. These permissions are granted (locally) to the
creator of any newly-created descendent file system.
.It Xo
.Nm
.Cm allow
.Fl s
.Ar @setname
.Ar perm Ns | Ns Ar @setname Ns Op Ns , Ns Ar perm Ns | Ns Ar @setname Ns
.Ns ...
.Ar filesystem Ns | Ns Ar volume
.Xc
.Pp
Defines or adds permissions to a permission set. The set can be used by other
.Qq Nm Cm allow
commands for the specified file system and its descendents. Sets are evaluated
dynamically, so changes to a set are immediately reflected. Permission sets
follow the same naming restrictions as ZFS file systems, but the name must
begin with an "at sign"
.Pq Sy @ ,
and can be no more than 64 characters long.
.It Xo
.Nm
.Cm unallow
.Op Fl rldug
.Ar user Ns | Ns Ar group Ns Oo Ns , Ns Ar user Ns | Ns Ar group Oc Ns ...
.Oo Ar perm Ns | Ns Ar @setname Ns Op , Ns Ar perm Ns | Ns Ar @setname Ns
.Ns ... Oc
.Ar filesystem Ns | Ns Ar volume
.Xc
.It Xo
.Nm
.Cm unallow
.Op Fl rld
.Fl e Ns | Ns Cm everyone
.Oo Ar perm Ns | Ns Ar @setname Ns Op , Ns Ar perm Ns | Ns Ar @setname Ns
.Ns ... Oc
.Ar filesystem Ns | Ns Ar volume
.Xc
.It Xo
.Nm
.Cm unallow
.Op Fl r
.Fl c
.Oo Ar perm Ns | Ns Ar @setname Ns Op , Ns Ar perm Ns | Ns Ar @setname Ns
.Ns ... Oc
.Ar filesystem Ns | Ns Ar volume
.Xc
.Pp
Removes permissions that were granted with the
.Qq Nm Cm allow
command. No permissions are explicitly denied, so other permissions granted are
still in effect. For example, if the permission is granted by an ancestor. If
no permissions are specified, then all permissions for the specified
.Ar user , group , No or everyone
are removed. Specifying
.Cm everyone
.Po or using the Fl e
option
.Pc only removes the permissions that were granted to everyone ,
not all permissions for every user and group. See the
.Qq Nm Cm allow
command for a description of the
.Fl ldugec
options.
.Bl -tag -width indent
.It Fl r
Recursively remove the permissions from this file system and all descendents.
.El
.It Xo
.Nm
.Cm unallow
.Op Fl r
.Fl s
.Ar @setname
.Oo Ar perm Ns | Ns Ar @setname Ns Op , Ns Ar perm Ns | Ns Ar @setname Ns
.Ns ... Oc
.Ar filesystem Ns | Ns Ar volume
.Xc
.Pp
Removes permissions from a permission set. If no permissions are specified,
then all permissions are removed, thus removing the set entirely.
.It Xo
.Nm
.Cm hold
.Op Fl r
.Ar tag snapshot Ns ...
.Xc
.Pp
Adds a single reference, named with the
.Ar tag
argument, to the specified snapshot or snapshots. Each snapshot has its own tag
namespace, and tags must be unique within that space.
.Pp
If a hold exists on a snapshot, attempts to destroy that snapshot by using the
.Qq Nm Cm destroy
command returns
.Em EBUSY .
.Bl -tag -width indent
.It Fl r
Specifies that a hold with the given tag is applied recursively to the
snapshots of all descendent file systems.
.El
.It Xo
.Nm
.Cm holds
.Op Fl r
.Ar snapshot Ns ...
.Xc
.Pp
Lists all existing user references for the given snapshot or snapshots.
.Bl -tag -width indent
.It Fl r
Lists the holds that are set on the named descendent snapshots, in addition to
listing the holds on the named snapshot.
.El
.It Xo
.Nm
.Cm release
.Op Fl r
.Ar tag snapshot Ns ...
.Xc
.Pp
Removes a single reference, named with the
.Ar tag
argument, from the specified snapshot or snapshots. The tag must already exist
for each snapshot.
.Bl -tag -width indent
.It Fl r
Recursively releases a hold with the given tag on the snapshots of all
descendent file systems.
.El
.It Xo
.Nm
.Cm diff
.Op Fl FHt
.Ar snapshot
.Op Ar snapshot Ns | Ns Ar filesystem
.Xc
.Pp
Display the difference between a snapshot of a given filesystem and another
snapshot of that filesystem from a later time or the current contents of the
filesystem.  The first column is a character indicating the type of change,
the other columns indicate pathname, new pathname
.Pq in case of rename ,
change in link count, and optionally file type and/or change time.
.Pp
The types of change are:
.Bl -column -offset 2n indent
.It \&- Ta path was removed
.It \&+ Ta path was added
.It \&M Ta path was modified
.It \&R Ta path was renamed
.El
.Bl -tag -width indent
.It Fl F
Display an indication of the type of file, in a manner similar to the
.Fl F
option of
.Xr ls 1 .
.Bl -column -offset 2n indent
.It \&B Ta block device
.It \&C Ta character device
.It \&F Ta regular file
.It \&/ Ta directory
.It \&@ Ta symbolic link
.It \&= Ta socket
.It \&> Ta door (not supported on Fx )
.It \&| Ta named pipe (not supported on Fx )
.It \&P Ta event port (not supported on Fx )
.El
.It Fl H
Give more parsable tab-separated output, without header lines and without
arrows.
.It Fl t
Display the path's inode change time as the first column of output.
.El
.It Xo
.Nm
.Cm jail
.Ar jailid filesystem
.Xc
.Pp
Attaches the specified
.Ar filesystem
to the jail identified by JID
.Ar jailid .
From now on this file system tree can be managed from within a jail if the
.Sy jailed
property has been set. To use this functionality, the jail needs the
.Va allow.mount
and
.Va allow.mount.zfs
parameters set to 1 and the
.Va enforce_statfs
parameter set to a value lower than 2.
.Pp
See
.Xr jail 8
for more information on managing jails and configuring the parameters above.
.It Xo
.Nm
.Cm unjail
.Ar jailid filesystem
.Xc
.Pp
Detaches the specified
.Ar filesystem
from the jail identified by JID
.Ar jailid .
.El
.Sh EXIT STATUS
The following exit values are returned:
.Bl -tag -offset 2n -width 2n
.It 0
Successful completion.
.It 1
An error occurred.
.It 2
Invalid command line options were specified.
.El
.Sh EXAMPLES
.Bl -tag -width 0n
.It Sy Example 1 No Creating a Tn ZFS No File System Hierarchy
.Pp
The following commands create a file system named
.Em pool/home
and a file system named
.Em pool/home/bob .
The mount point
.Pa /home
is set for the parent file system, and is automatically inherited by the child
file system.
.Bd -literal -offset 2n
.Li # Ic zfs create pool/home
.Li # Ic zfs set mountpoint=/home pool/home
.Li # Ic zfs create pool/home/bob
.Ed
.It Sy Example 2 No Creating a Tn ZFS No Snapshot
.Pp
The following command creates a snapshot named
.Sy yesterday .
This snapshot is mounted on demand in the
.Pa \&.zfs/snapshot
directory at the root of the
.Em pool/home/bob
file system.
.Bd -literal -offset 2n
.Li # Ic zfs snapshot pool/home/bob@yesterday
.Ed
.It Sy Example 3 No Creating and Destroying Multiple Snapshots
.Pp
The following command creates snapshots named
.Em yesterday
of
.Em pool/home
and all of its descendent file systems. Each snapshot is mounted on demand in
the
.Pa \&.zfs/snapshot
directory at the root of its file system. The second command destroys the newly
created snapshots.
.Bd -literal -offset 2n
.Li # Ic zfs snapshot -r pool/home@yesterday
.Li # Ic zfs destroy -r pool/home@yesterday
.Ed
.It Sy Example 4 No Disabling and Enabling File System Compression
.Pp
The following command disables the
.Sy compression
property for all file systems under
.Em pool/home .
The next command explicitly enables
.Sy compression
for
.Em pool/home/anne .
.Bd -literal -offset 2n
.Li # Ic zfs set compression=off pool/home
.Li # Ic zfs set compression=on pool/home/anne
.Ed
.It Sy Example 5 No Listing Tn ZFS No Datasets
.Pp
The following command lists all active file systems and volumes in the system.
Snapshots are displayed if the
.Sy listsnaps
property is
.Cm on .
The default is
.Cm off .
See
.Xr zpool 8
for more information on pool properties.
.Bd -literal -offset 2n
.Li # Ic zfs list
   NAME                      USED  AVAIL  REFER  MOUNTPOINT
   pool                      450K   457G    18K  /pool
   pool/home                 315K   457G    21K  /home
   pool/home/anne             18K   457G    18K  /home/anne
   pool/home/bob             276K   457G   276K  /home/bob
.Ed
.It Sy Example 6 No Setting a Quota on a Tn ZFS No File System
.Pp
The following command sets a quota of 50 Gbytes for
.Em pool/home/bob .
.Bd -literal -offset 2n
.Li # Ic zfs set quota=50G pool/home/bob
.Ed
.It Sy Example 7 No Listing Tn ZFS No Properties
.Pp
The following command lists all properties for
.Em pool/home/bob .
.Bd -literal -offset 2n
.Li # Ic zfs get all pool/home/bob
NAME           PROPERTY              VALUE                  SOURCE
pool/home/bob  type                  filesystem             -
pool/home/bob  creation              Tue Jul 21 15:53 2009  -
pool/home/bob  used                  21K                    -
pool/home/bob  available             20.0G                  -
pool/home/bob  referenced            21K                    -
pool/home/bob  compressratio         1.00x                  -
pool/home/bob  mounted               yes                    -
pool/home/bob  quota                 20G                    local
pool/home/bob  reservation           none                   default
pool/home/bob  recordsize            128K                   default
pool/home/bob  mountpoint            /home/bob              default
pool/home/bob  sharenfs              off                    default
pool/home/bob  checksum              on                     default
pool/home/bob  compression           on                     local
pool/home/bob  atime                 on                     default
pool/home/bob  devices               on                     default
pool/home/bob  exec                  on                     default
pool/home/bob  filesystem_limit      none                   default
pool/home/bob  setuid                on                     default
pool/home/bob  readonly              off                    default
pool/home/bob  jailed                off                    default
pool/home/bob  snapdir               hidden                 default
pool/home/bob  snapshot_limit        none                   default
pool/home/bob  aclmode               discard                default
pool/home/bob  aclinherit            restricted             default
pool/home/bob  canmount              on                     default
pool/home/bob  xattr                 on                     default
pool/home/bob  copies                1                      default
pool/home/bob  version               5                      -
pool/home/bob  utf8only              off                    -
pool/home/bob  normalization         none                   -
pool/home/bob  casesensitivity       sensitive              -
pool/home/bob  vscan                 off                    default
pool/home/bob  nbmand                off                    default
pool/home/bob  sharesmb              off                    default
pool/home/bob  refquota              none                   default
pool/home/bob  refreservation        none                   default
pool/home/bob  primarycache          all                    default
pool/home/bob  secondarycache        all                    default
pool/home/bob  usedbysnapshots       0                      -
pool/home/bob  usedbydataset         21K                    -
pool/home/bob  usedbychildren        0                      -
pool/home/bob  usedbyrefreservation  0                      -
pool/home/bob  logbias               latency                default
pool/home/bob  dedup                 off                    default
pool/home/bob  mlslabel                                     -
pool/home/bob  sync                  standard               default
pool/home/bob  refcompressratio      1.00x                  -
.Ed
.Pp
The following command gets a single property value.
.Bd -literal -offset 2n
.Li # Ic zfs get -H -o value compression pool/home/bob
on
.Ed
.Pp
The following command lists all properties with local settings for
.Em pool/home/bob .
.Bd -literal -offset 2n
.Li # Ic zfs get -s local -o name,property,value all pool/home/bob
NAME           PROPERTY              VALUE
pool/home/bob  quota                 20G
pool/home/bob  compression           on
.Ed
.It Sy Example 8 No Rolling Back a Tn ZFS No File System
.Pp
The following command reverts the contents of
.Em pool/home/anne
to the snapshot named
.Em yesterday ,
deleting all intermediate snapshots.
.Bd -literal -offset 2n
.Li # Ic zfs rollback -r pool/home/anne@yesterday
.Ed
.It Sy Example 9 No Creating a Tn ZFS No Clone
.Pp
The following command creates a writable file system whose initial contents are
the same as
.Em pool/home/bob@yesterday .
.Bd -literal -offset 2n
.Li # Ic zfs clone pool/home/bob@yesterday pool/clone
.Ed
.It Sy Example 10 No Promoting a Tn ZFS No Clone
.Pp
The following commands illustrate how to test out changes to a file system, and
then replace the original file system with the changed one, using clones, clone
promotion, and renaming:
.Bd -literal -offset 2n
.Li # Ic zfs create pool/project/production
.Ed
.Pp
Populate
.Pa /pool/project/production
with data and continue with the following commands:
.Bd -literal -offset 2n
.Li # Ic zfs snapshot pool/project/production@today
.Li # Ic zfs clone pool/project/production@today pool/project/beta
.Ed
.Pp
Now make changes to
.Pa /pool/project/beta
and continue with the following commands:
.Bd -literal -offset 2n
.Li # Ic zfs promote pool/project/beta
.Li # Ic zfs rename pool/project/production pool/project/legacy
.Li # Ic zfs rename pool/project/beta pool/project/production
.Ed
.Pp
Once the legacy version is no longer needed, it can be destroyed.
.Bd -literal -offset 2n
.Li # Ic zfs destroy pool/project/legacy
.Ed
.It Sy Example 11 No Inheriting Tn ZFS No Properties
.Pp
The following command causes
.Em pool/home/bob
and
.Em pool/home/anne
to inherit the
.Sy checksum
property from their parent.
.Bd -literal -offset 2n
.Li # Ic zfs inherit checksum pool/home/bob pool/home/anne
.Ed
.It Sy Example 12 No Remotely Replicating Tn ZFS No Data
.Pp
The following commands send a full stream and then an incremental stream to a
remote machine, restoring them into
.Sy poolB/received/fs@a
and
.Sy poolB/received/fs@b ,
respectively.
.Sy poolB
must contain the file system
.Sy poolB/received ,
and must not initially contain
.Sy poolB/received/fs .
.Bd -literal -offset 2n
.Li # Ic zfs send pool/fs@a | ssh host zfs receive poolB/received/fs@a
.Li # Ic zfs send -i a pool/fs@b | ssh host zfs receive poolB/received/fs
.Ed
.It Xo
.Sy Example 13
Using the
.Qq zfs receive -d
Option
.Xc
.Pp
The following command sends a full stream of
.Sy poolA/fsA/fsB@snap
to a remote machine, receiving it into
.Sy poolB/received/fsA/fsB@snap .
The
.Sy fsA/fsB@snap
portion of the received snapshot's name is determined from the name of the sent
snapshot.
.Sy poolB
must contain the file system
.Sy poolB/received .
If
.Sy poolB/received/fsA
does not exist, it is created as an empty file system.
.Bd -literal -offset 2n
.Li # Ic zfs send poolA/fsA/fsB@snap | ssh host zfs receive -d poolB/received
.Ed
.It Sy Example 14 No Setting User Properties
.Pp
The following example sets the user-defined
.Sy com.example:department
property for a dataset.
.Bd -literal -offset 2n
.Li # Ic zfs set com.example:department=12345 tank/accounting
.Ed
.It Sy Example 15 No Performing a Rolling Snapshot
.Pp
The following example shows how to maintain a history of snapshots with a
consistent naming scheme. To keep a week's worth of snapshots, the user
destroys the oldest snapshot, renames the remaining snapshots, and then creates
a new snapshot, as follows:
.Bd -literal -offset 2n
.Li # Ic zfs destroy -r pool/users@7daysago
.Li # Ic zfs rename -r pool/users@6daysago @7daysago
.Li # Ic zfs rename -r pool/users@5daysago @6daysago
.Li # Ic zfs rename -r pool/users@4daysago @5daysago
.Li # Ic zfs rename -r pool/users@3daysago @4daysago
.Li # Ic zfs rename -r pool/users@2daysago @3daysago
.Li # Ic zfs rename -r pool/users@yesterday @2daysago
.Li # Ic zfs rename -r pool/users@today @yesterday
.Li # Ic zfs snapshot -r pool/users@today
.Ed
.It Xo
.Sy Example 16
Setting
.Qq sharenfs
Property Options on a ZFS File System
.Xc
.Pp
The following command shows how to set
.Sy sharenfs
property options to enable root access for a specific network on the
.Em tank/home
file system. The contents of the
.Sy sharenfs
property are valid
.Xr exports 5
options.
.Bd -literal -offset 2n
.Li # Ic zfs set sharenfs="maproot=root,network 192.168.0.0/24" tank/home
.Ed
.Pp
Another way to write this command with the same result is:
.Bd -literal -offset 2n
.Li # Ic set zfs sharenfs="-maproot=root -network 192.168.0.0/24" tank/home
.Ed
.It Xo
.Sy Example 17
Delegating
.Tn ZFS
Administration Permissions on a
.Tn ZFS
Dataset
.Xc
.Pp
The following example shows how to set permissions so that user
.Em cindys
can create, destroy, mount, and take snapshots on
.Em tank/cindys .
The permissions on
.Em tank/cindys
are also displayed.
.Bd -literal -offset 2n
.Li # Ic zfs allow cindys create,destroy,mount,snapshot tank/cindys
.Li # Ic zfs allow tank/cindys
---- Permissions on tank/cindys --------------------------------------
Local+Descendent permissions:
        user cindys create,destroy,mount,snapshot
.Ed
.It Sy Example 18 No Delegating Create Time Permissions on a Tn ZFS No Dataset
.Pp
The following example shows how to grant anyone in the group
.Em staff
to create file systems in
.Em tank/users .
This syntax also allows staff members to destroy their own file systems, but
not destroy anyone else's file system. The permissions on
.Em tank/users
are also displayed.
.Bd -literal -offset 2n
.Li # Ic zfs allow staff create,mount tank/users
.Li # Ic zfs allow -c destroy tank/users
.Li # Ic zfs allow tank/users
---- Permissions on tank/users ---------------------------------------
Permission sets:
        destroy
Local+Descendent permissions:
        group staff create,mount
.Ed
.It Xo
.Sy Example 19
Defining and Granting a Permission Set on a
.Tn ZFS
Dataset
.Xc
.Pp
The following example shows how to define and grant a permission set on the
.Em tank/users
file system. The permissions on
.Em tank/users
are also displayed.
.Bd -literal -offset 2n
.Li # Ic zfs allow -s @pset create,destroy,snapshot,mount tank/users
.Li # Ic zfs allow staff @pset tank/users
.Li # Ic zfs allow tank/users
---- Permissions on tank/users ---------------------------------------
Permission sets:
        @pset create,destroy,mount,snapshot
Local+Descendent permissions:
        group staff @pset
.Ed
.It Sy Example 20 No Delegating Property Permissions on a Tn ZFS No Dataset
.Pp
The following example shows to grant the ability to set quotas and reservations
on the
.Sy users/home
file system. The permissions on
.Sy users/home
are also displayed.
.Bd -literal -offset 2n
.Li # Ic zfs allow cindys quota,reservation users/home
.Li # Ic zfs allow users/home
---- Permissions on users/home ---------------------------------------
Local+Descendent permissions:
        user cindys quota,reservation
.Li # Ic su - cindys
.Li cindys% Ic zfs set quota=10G users/home/marks
.Li cindys% Ic zfs get quota users/home/marks
NAME              PROPERTY  VALUE  SOURCE
users/home/marks  quota     10G    local
.Ed
.It Sy Example 21 No Removing ZFS Delegated Permissions on a Tn ZFS No Dataset
.Pp
The following example shows how to remove the snapshot permission from the
.Em staff
group on the
.Em tank/users
file system. The permissions on
.Em tank/users
are also displayed.
.Bd -literal -offset 2n
.Li # Ic zfs unallow staff snapshot tank/users
.Li # Ic zfs allow tank/users
---- Permissions on tank/users ---------------------------------------
Permission sets:
        @pset create,destroy,mount,snapshot
Local+Descendent permissions:
        group staff @pset
.Ed
.It Sy Example 22 Showing the differences between a snapshot and a ZFS Dataset
.Pp
The following example shows how to see what has changed between a prior
snapshot of a ZFS Dataset and its current state.  The
.Fl F
option is used to indicate type information for the files affected.
.Bd -literal -offset 2n
.Li # Ic zfs diff tank/test@before tank/test
M       /       /tank/test/
M       F       /tank/test/linked      (+1)
R       F       /tank/test/oldname -> /tank/test/newname
-       F       /tank/test/deleted
+       F       /tank/test/created
M       F       /tank/test/modified
.Ed
.El
.Sh SEE ALSO
.Xr chmod 2 ,
.Xr fsync 2 ,
.Xr exports 5 ,
.Xr fstab 5 ,
.Xr rc.conf 5 ,
.Xr jail 8 ,
.Xr mount 8 ,
.Xr umount 8 ,
.Xr zpool 8
.Sh AUTHORS
This manual page is a
.Xr mdoc 7
reimplementation of the
.Tn OpenSolaris
manual page
.Em zfs(1M) ,
modified and customized for
.Fx
and licensed under the
Common Development and Distribution License
.Pq Tn CDDL .
.Pp
The
.Xr mdoc 7
implementation of this manual page was initially written by
.An Martin Matuska Aq mm@FreeBSD.org .