1e001b99a5
so don't imply that. Note that if BIO_DELETE isn't supported, the operation will fail (as opposed to writing the entire disk with zeros). Thin storage also benefits from trim. List more accurate reason why trim helps flash-memory.
334 lines
10 KiB
Groff
334 lines
10 KiB
Groff
.\" Copyright (c) 1983, 1987, 1991, 1993, 1994
|
|
.\" The Regents of the University of California. All rights reserved.
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\" 3. Neither the name of the University nor the names of its contributors
|
|
.\" may be used to endorse or promote products derived from this software
|
|
.\" without specific prior written permission.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
|
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
|
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
.\" SUCH DAMAGE.
|
|
.\"
|
|
.\" @(#)newfs.8 8.6 (Berkeley) 5/3/95
|
|
.\" $FreeBSD$
|
|
.\"
|
|
.Dd July 15, 2015
|
|
.Dt NEWFS 8
|
|
.Os
|
|
.Sh NAME
|
|
.Nm newfs
|
|
.Nd construct a new UFS1/UFS2 file system
|
|
.Sh SYNOPSIS
|
|
.Nm
|
|
.Op Fl EJNUjlnt
|
|
.Op Fl L Ar volname
|
|
.Op Fl O Ar filesystem-type
|
|
.Op Fl S Ar sector-size
|
|
.Op Fl T Ar disktype
|
|
.Op Fl a Ar maxcontig
|
|
.Op Fl b Ar block-size
|
|
.Op Fl c Ar blocks-per-cylinder-group
|
|
.Op Fl d Ar max-extent-size
|
|
.Op Fl e Ar maxbpg
|
|
.Op Fl f Ar frag-size
|
|
.Op Fl g Ar avgfilesize
|
|
.Op Fl h Ar avgfpdir
|
|
.Op Fl i Ar bytes
|
|
.Op Fl k Ar held-for-metadata-blocks
|
|
.Op Fl m Ar free-space
|
|
.Op Fl o Ar optimization
|
|
.Op Fl p Ar partition
|
|
.Op Fl r Ar reserved
|
|
.Op Fl s Ar size
|
|
.Ar special
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Nm
|
|
utility is used to initialize and clear file systems before first use.
|
|
The
|
|
.Nm
|
|
utility builds a file system on the specified special file.
|
|
(We often refer to the
|
|
.Dq special file
|
|
as the
|
|
.Dq disk ,
|
|
although the special file need not be a physical disk.
|
|
In fact, it need not even be special.)
|
|
Typically the defaults are reasonable, however
|
|
.Nm
|
|
has numerous options to allow the defaults to be selectively overridden.
|
|
.Pp
|
|
The following options define the general layout policies:
|
|
.Bl -tag -width indent
|
|
.It Fl E
|
|
Erase the content of the disk before making the filesystem.
|
|
The reserved area in front of the superblock (for bootcode) will not be erased.
|
|
Erasing is only relevant to flash-memory or thinly provisioned devices.
|
|
Erasing may take a long time.
|
|
If the device does not support BIO_DELETE, the command will fail.
|
|
.It Fl J
|
|
Enable journaling on the new file system via gjournal.
|
|
See
|
|
.Xr gjournal 8
|
|
for details.
|
|
.It Fl L Ar volname
|
|
Add a volume label to the new file system.
|
|
.It Fl N
|
|
Cause the file system parameters to be printed out
|
|
without really creating the file system.
|
|
.It Fl O Ar filesystem-type
|
|
Use 1 to specify that a UFS1 format file system be built;
|
|
use 2 to specify that a UFS2 format file system be built.
|
|
The default format is UFS2.
|
|
.It Fl T Ar disktype
|
|
For backward compatibility.
|
|
.It Fl U
|
|
Enable soft updates on the new file system.
|
|
.It Fl a Ar maxcontig
|
|
Specify the maximum number of contiguous blocks that will be
|
|
laid out before forcing a rotational delay.
|
|
The default value is 16.
|
|
See
|
|
.Xr tunefs 8
|
|
for more details on how to set this option.
|
|
.It Fl b Ar block-size
|
|
The block size of the file system, in bytes.
|
|
It must be a power of 2.
|
|
The
|
|
default size is 32768 bytes, and the smallest allowable size is 4096 bytes.
|
|
The optimal block:fragment ratio is 8:1.
|
|
Other ratios are possible, but are not recommended,
|
|
and may produce poor results.
|
|
.It Fl c Ar blocks-per-cylinder-group
|
|
The number of blocks per cylinder group in a file system.
|
|
The default is to compute the maximum allowed by the other parameters.
|
|
This value is
|
|
dependent on a number of other parameters, in particular the block size
|
|
and the number of bytes per inode.
|
|
.It Fl d Ar max-extent-size
|
|
The file system may choose to store large files using extents.
|
|
This parameter specifies the largest extent size that may be used.
|
|
The default value is the file system blocksize.
|
|
It is presently limited to a maximum value of 16 times the
|
|
file system blocksize and a minimum value of the file system blocksize.
|
|
.It Fl e Ar maxbpg
|
|
Indicate the maximum number of blocks any single file can
|
|
allocate out of a cylinder group before it is forced to begin
|
|
allocating blocks from another cylinder group.
|
|
The default is about one quarter of the total blocks in a cylinder group.
|
|
See
|
|
.Xr tunefs 8
|
|
for more details on how to set this option.
|
|
.It Fl f Ar frag-size
|
|
The fragment size of the file system in bytes.
|
|
It must be a power of two
|
|
ranging in value between
|
|
.Ar blocksize Ns /8
|
|
and
|
|
.Ar blocksize .
|
|
The default is 4096 bytes.
|
|
.It Fl g Ar avgfilesize
|
|
The expected average file size for the file system.
|
|
.It Fl h Ar avgfpdir
|
|
The expected average number of files per directory on the file system.
|
|
.It Fl i Ar bytes
|
|
Specify the density of inodes in the file system.
|
|
The default is to create an inode for every
|
|
.Pq 2 * Ar frag-size
|
|
bytes of data space.
|
|
If fewer inodes are desired, a larger number should be used;
|
|
to create more inodes a smaller number should be given.
|
|
One inode is required for each distinct file, so this value effectively
|
|
specifies the average file size on the file system.
|
|
.It Fl j
|
|
Enable soft updates journaling on the new file system.
|
|
This flag is implemented by running the
|
|
.Xr tunefs 8
|
|
utility found in the user's
|
|
.Dv $PATH .
|
|
.It Fl k Ar held-for-metadata-blocks
|
|
Set the amount of space to be held for metadata blocks in each cylinder group.
|
|
When set, the file system preference routines will try to save
|
|
the specified amount of space immediately following the inode blocks
|
|
in each cylinder group for use by metadata blocks.
|
|
Clustering the metadata blocks speeds up random file access
|
|
and decreases the running time of
|
|
.Xr fsck 8 .
|
|
By default
|
|
.Nm
|
|
sets it to half of the space reserved to minfree.
|
|
.It Fl l
|
|
Enable multilabel MAC on the new file system.
|
|
.It Fl m Ar free-space
|
|
The percentage of space reserved from normal users; the minimum free
|
|
space threshold.
|
|
The default value used is
|
|
defined by
|
|
.Dv MINFREE
|
|
from
|
|
.In ufs/ffs/fs.h ,
|
|
currently 8%.
|
|
See
|
|
.Xr tunefs 8
|
|
for more details on how to set this option.
|
|
.It Fl n
|
|
Do not create a
|
|
.Pa .snap
|
|
directory on the new file system.
|
|
The resulting file system will not support snapshot generation, so
|
|
.Xr dump 8
|
|
in live mode and background
|
|
.Xr fsck 8
|
|
will not function properly.
|
|
The traditional
|
|
.Xr fsck 8
|
|
and offline
|
|
.Xr dump 8
|
|
will work on the file system.
|
|
This option is intended primarily for memory or vnode-backed file systems that
|
|
do not require
|
|
.Xr dump 8
|
|
or
|
|
.Xr fsck 8
|
|
support.
|
|
.It Fl o Ar optimization
|
|
.Cm ( space
|
|
or
|
|
.Cm time ) .
|
|
The file system can either be instructed to try to minimize the time spent
|
|
allocating blocks, or to try to minimize the space fragmentation on the disk.
|
|
If the value of minfree (see above) is less than 8%,
|
|
the default is to optimize for
|
|
.Cm space ;
|
|
if the value of minfree is greater than or equal to 8%,
|
|
the default is to optimize for
|
|
.Cm time .
|
|
See
|
|
.Xr tunefs 8
|
|
for more details on how to set this option.
|
|
.It Fl p Ar partition
|
|
The partition name (a..h) you want to use in case the underlying image
|
|
is a file, so you do not have access to individual partitions through the
|
|
filesystem.
|
|
Can also be used with a device, e.g.,
|
|
.Nm
|
|
.Fl p Ar f
|
|
.Ar /dev/da1s3
|
|
is equivalent to
|
|
.Nm
|
|
.Ar /dev/da1s3f .
|
|
.It Fl r Ar reserved
|
|
The size, in sectors, of reserved space
|
|
at the end of the partition specified in
|
|
.Ar special .
|
|
This space will not be occupied by the file system;
|
|
it can be used by other consumers such as
|
|
.Xr geom 4 .
|
|
Defaults to 0.
|
|
.It Fl s Ar size
|
|
The size of the file system in sectors.
|
|
This value defaults to the size of the
|
|
raw partition specified in
|
|
.Ar special
|
|
less the
|
|
.Ar reserved
|
|
space at its end (see
|
|
.Fl r ) .
|
|
A
|
|
.Ar size
|
|
of 0 can also be used to choose the default value.
|
|
A valid
|
|
.Ar size
|
|
value cannot be larger than the default one,
|
|
which means that the file system cannot extend into the reserved space.
|
|
.It Fl t
|
|
Turn on the TRIM enable flag.
|
|
If enabled, and if the underlying device supports the BIO_DELETE
|
|
command, the file system will send a delete request to the underlying
|
|
device for each freed block.
|
|
The trim enable flag is typically set for flash-memory devices to
|
|
reduce write amplification which reduces wear on write-limited
|
|
flash-memory and often improves long-term performance.
|
|
Thinly provisioned storage also benefits by returning unused blocks to
|
|
the global pool.
|
|
.El
|
|
.Pp
|
|
The following options override the standard sizes for the disk geometry.
|
|
Their default values are taken from the disk label.
|
|
Changing these defaults is useful only when using
|
|
.Nm
|
|
to build a file system whose raw image will eventually be used on a
|
|
different type of disk than the one on which it is initially created
|
|
(for example on a write-once disk).
|
|
Note that changing any of these values from their defaults will make
|
|
it impossible for
|
|
.Xr fsck 8
|
|
to find the alternate superblocks if the standard superblock is lost.
|
|
.Bl -tag -width indent
|
|
.It Fl S Ar sector-size
|
|
The size of a sector in bytes (almost never anything but 512).
|
|
.El
|
|
.Sh EXAMPLES
|
|
.Dl newfs /dev/ada3s1a
|
|
.Pp
|
|
Creates a new ufs file system on
|
|
.Pa ada3s1a .
|
|
The
|
|
.Nm
|
|
utility will use a block size of 32768 bytes, a fragment size of 4096 bytes
|
|
and the largest possible number of blocks per cylinders group.
|
|
These values tend to produce better performance for most applications
|
|
than the historical defaults
|
|
(8192 byte block size and 1024 byte fragment size).
|
|
This large fragment size may lead to much wasted space
|
|
on file systems that contain many small files.
|
|
.Sh SEE ALSO
|
|
.Xr fdformat 1 ,
|
|
.Xr geom 4 ,
|
|
.Xr disktab 5 ,
|
|
.Xr fs 5 ,
|
|
.Xr camcontrol 8 ,
|
|
.Xr dump 8 ,
|
|
.Xr dumpfs 8 ,
|
|
.Xr fsck 8 ,
|
|
.Xr gpart 8 ,
|
|
.Xr gjournal 8 ,
|
|
.Xr growfs 8 ,
|
|
.Xr gvinum 8 ,
|
|
.Xr makefs 8 ,
|
|
.Xr mount 8 ,
|
|
.Xr tunefs 8
|
|
.Rs
|
|
.%A M. McKusick
|
|
.%A W. Joy
|
|
.%A S. Leffler
|
|
.%A R. Fabry
|
|
.%T A Fast File System for UNIX
|
|
.%J ACM Transactions on Computer Systems 2
|
|
.%V 3
|
|
.%P pp 181-197
|
|
.%D August 1984
|
|
.%O (reprinted in the BSD System Manager's Manual)
|
|
.Re
|
|
.Sh HISTORY
|
|
The
|
|
.Nm
|
|
utility appeared in
|
|
.Bx 4.2 .
|