380 lines
12 KiB
Groff
380 lines
12 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. All advertising materials mentioning features or use of this software
|
|
.\" must display the following acknowledgement:
|
|
.\" This product includes software developed by the University of
|
|
.\" California, Berkeley and its contributors.
|
|
.\" 4. 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 May 3, 1995
|
|
.Dt NEWFS 8
|
|
.Os BSD 4.2
|
|
.Sh NAME
|
|
.Nm newfs ,
|
|
.Nm mount_mfs
|
|
.Nd construct a new file system
|
|
.Sh SYNOPSIS
|
|
.Nm newfs
|
|
.Op Fl NO
|
|
.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 cylinders
|
|
.Op Fl d Ar rotdelay
|
|
.Op Fl e Ar maxbpg
|
|
.Op Fl f Ar frag-size
|
|
.Op Fl i Ar bytes
|
|
.Op Fl k Ar skew
|
|
.Op Fl l Ar interleave
|
|
.Op Fl m Ar free space
|
|
.Op Fl n Ar rotational positions
|
|
.Op Fl o Ar optimization
|
|
.Op Fl p Ar sectors
|
|
.Op Fl r Ar revolutions
|
|
.Op Fl s Ar size
|
|
.Op Fl t Ar tracks
|
|
.Op Fl u Ar sectors
|
|
.Op Fl v
|
|
.Op Fl x Ar sectors
|
|
.Ar special
|
|
.Nm mount_mfs
|
|
.Op Fl N
|
|
.Op Fl F Ar file
|
|
.Op Fl T Ar disktype
|
|
.Op Fl a Ar maxcontig
|
|
.Op Fl b Ar block-size
|
|
.Op Fl c Ar cylinders
|
|
.Op Fl d Ar rotdelay
|
|
.Op Fl e Ar maxbpg
|
|
.Op Fl f Ar frag-size
|
|
.Op Fl i Ar bytes
|
|
.Op Fl m Ar free space
|
|
.Op Fl n Ar rotational positions
|
|
.Op Fl o Ar options
|
|
.Op Fl s Ar size
|
|
.Ar special node
|
|
.Sh DESCRIPTION
|
|
.Nm Newfs
|
|
replaces the more obtuse
|
|
.Xr mkfs 8
|
|
program.
|
|
Before running
|
|
.Nm
|
|
or
|
|
.Nm mount_mfs ,
|
|
the disk must be labeled using
|
|
.Xr disklabel 8 .
|
|
.Nm Newfs
|
|
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
|
|
.Nm Mount_mfs
|
|
is used to build a file system in virtual memory and then mount it
|
|
on a specified node.
|
|
.Nm Mount_mfs
|
|
exits and the contents of the file system are lost
|
|
when the file system is unmounted.
|
|
If
|
|
.Nm mount_mfs
|
|
is sent a signal while running,
|
|
for example during system shutdown,
|
|
it will attempt to unmount its
|
|
corresponding file system.
|
|
The parameters to
|
|
.Nm mount_mfs
|
|
are the same as those to
|
|
.Nm Ns .
|
|
If the
|
|
.Fl T
|
|
flag is specified (see below), the special file is unused.
|
|
Otherwise, it is only used to read the disk label which provides
|
|
a set of configuration parameters for the memory based file system.
|
|
The special file is typically that of the primary swap area,
|
|
since that is where the file system will be backed up when
|
|
free memory gets low and the memory supporting
|
|
the file system has to be paged.
|
|
.Pp
|
|
The following options define the general layout policies:
|
|
.Bl -tag -width indent
|
|
.It Fl T Ar disktype
|
|
For backward compatibility and for
|
|
.Nm mount_mfs .
|
|
.It Fl F Ar file
|
|
.Nm Mount_mfs
|
|
will use this file for the image of the filesystem. When
|
|
.Nm mount_mfs
|
|
exits, this file will be left behind.
|
|
.It Fl N
|
|
Cause the file system parameters to be printed out
|
|
without really creating the file system.
|
|
.It Fl O
|
|
Create a
|
|
.Bx 4.3
|
|
format filesystem.
|
|
This options is primarily used to build root filesystems
|
|
that can be understood by older boot ROMs.
|
|
.It Fl T
|
|
Use information for the specified disk from
|
|
.Pa /etc/disktab
|
|
instead of trying to get the information from a disklabel.
|
|
.It Fl a Ar maxcontig
|
|
Specify the maximum number of contiguous blocks that will be
|
|
laid out before forcing a rotational delay (see the
|
|
.Fl d
|
|
option).
|
|
The default value is 1.
|
|
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 8192 bytes, and the smallest allowable size is 4096 bytes.
|
|
.It Fl c Ar #cylinders/group
|
|
The number of cylinders per cylinder group in a file system. The default value
|
|
is 16. The maximum value is dependent on a number of other parameters, in
|
|
particular the block size. The best way to find the maximum value for a
|
|
specific file system is to attempt to specify a value which is far too large:
|
|
.Nm
|
|
will print out the maximum value.
|
|
.It Fl d Ar rotdelay
|
|
This parameter once specified the minimum time in milliseconds required to
|
|
initiate another disk transfer on the same cylinder. It was used in determining
|
|
the rotationally optimal layout for disk blocks within a file. Modern disks
|
|
with read/write-behind achieve higher performance with this feature disabled, so
|
|
this value should be left at the default value of 0 milliseconds. See
|
|
.Xr tunefs 8
|
|
for more details on how to set this option.
|
|
.ne 1i
|
|
.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/8
|
|
and
|
|
.Ar blocksize .
|
|
The default is 1024 bytes.
|
|
.It Fl i Ar number of bytes per inode
|
|
Specify the density of inodes in the file system.
|
|
The default is to create an inode for every (4 * 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 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
|
|
.Ao Pa ufs/ffs/fs.h Ac ,
|
|
currently 8%.
|
|
See
|
|
.Xr tunefs 8
|
|
for more details on how to set this option.
|
|
.It Fl n Ar number of distinguished rotational positions
|
|
UFS has the ability to keep track of the availability of blocks at different
|
|
rotational positions, so that it could lay out the data to be picked up with
|
|
minimum rotational latency. This parameter specifies the default number of
|
|
rotational positions to distinguish.
|
|
.Pp
|
|
Nowadays this value should be set to 1 (which essentially disables the
|
|
rotational position table) because modern drives with read-ahead and
|
|
write-behind do better without the rotational position table.
|
|
.It Fl o Ar optimization\ preference
|
|
.Pq ``space'' or ``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 space;
|
|
if the value of minfree is greater than or equal to 8%,
|
|
the default is to optimize for time.
|
|
See
|
|
.Xr tunefs 8
|
|
for more details on how to set this option.
|
|
.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
|
|
(in other words,
|
|
.Nm
|
|
will use the entire partition for the file system).
|
|
.It Fl v
|
|
Specify that the disk does not contain any partitions, and that
|
|
.Nm
|
|
should build a file system on the whole disk.
|
|
This option is useful for synthetic disks such as
|
|
.Nm vinum.
|
|
.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).
|
|
.It Fl k Ar sector \&0 skew , per track
|
|
Used to describe perturbations in the media format to compensate for
|
|
a slow controller.
|
|
Track skew is the offset of sector 0 on track N relative to sector 0
|
|
on track N-1 on the same cylinder.
|
|
This option is of historical importance only; modern controllers are always fast
|
|
enough to handle operations back-to-back.
|
|
.It Fl l Ar hardware sector interleave
|
|
Used to describe perturbations in the media format to compensate for
|
|
a slow controller.
|
|
Interleave is physical sector interleave on each track,
|
|
specified as the denominator of the ratio:
|
|
.Dl sectors read/sectors passed over
|
|
Thus an interleave of 1/1 implies contiguous layout, while 1/2 implies
|
|
logical sector 0 is separated by one sector from logical sector 1.
|
|
This option is of historical importance only; the physical sector layout of
|
|
modern disks is not visible from outside.
|
|
.It Fl p Ar spare sectors per track
|
|
Spare sectors (bad sector replacements) are physical sectors that occupy
|
|
space at the end of each track.
|
|
They are not counted as part of the sectors/track
|
|
.Pq Fl u
|
|
since they are not available to the file system for data allocation.
|
|
This option is of historical importance only. Modern disks perform their own
|
|
bad sector allocation.
|
|
.It Fl r Ar revolutions/minute
|
|
The speed of the disk in revolutions per minute. This value is no longer of
|
|
interest, since all the parameters which depend on it are usually disabled.
|
|
.ne 1i
|
|
.It Fl t Ar #tracks/cylinder
|
|
The number of tracks/cylinder available for data allocation by the file
|
|
system.
|
|
The default is 1.
|
|
If zero is specified, the value from the disklabel will be used.
|
|
.It Fl u Ar sectors/track
|
|
The number of sectors per track available for data allocation by the file
|
|
system.
|
|
The default is 4096.
|
|
If zero is specified, the value from the disklabel will be used.
|
|
This does not include sectors reserved at the end of each track for bad
|
|
block replacement (see the
|
|
.Fl p
|
|
option).
|
|
.It Fl x Ar spare sectors per cylinder
|
|
Spare sectors (bad sector replacements) are physical sectors that occupy
|
|
space at the end of the last track in the cylinder.
|
|
They are deducted from the sectors/track
|
|
.Pq Fl u
|
|
of the last track of each cylinder since they are not available to the file
|
|
system for data allocation.
|
|
This option is of historical importance only. Modern disks perform their own
|
|
bad sector allocation.
|
|
.El
|
|
.Pp
|
|
The options to the
|
|
.Nm mount_mfs
|
|
command are as described for the
|
|
.Nm
|
|
command, except for the
|
|
.Fl o
|
|
option.
|
|
.Pp
|
|
That option is as follows:
|
|
.Bl -tag -width indent
|
|
.It Fl o
|
|
Options are specified with a
|
|
.Fl o
|
|
flag followed by a comma separated string of options.
|
|
See the
|
|
.Xr mount 8
|
|
man page for possible options and their meanings.
|
|
.El
|
|
.Sh EXAMPLES
|
|
.Pp
|
|
.Dl mount_mfs -s 131072 -o nosuid,nodev /dev/da0s1b /tmp
|
|
.Pp
|
|
Mount a 64 MB large memory file system on /tmp, with
|
|
.Xr mount 8
|
|
options nosuid and nodev.
|
|
.Sh BUGS
|
|
The boot code of
|
|
.Bx Free
|
|
assumes that the file system that carries the
|
|
kernel has blocks of 8 kilobytes and fragments of 1 kilobyte. You will
|
|
not be able to boot from a file system that uses another size.
|
|
.Sh SEE ALSO
|
|
.Xr fdformat 1 ,
|
|
.Xr disktab 5 ,
|
|
.Xr fs 5 ,
|
|
.Xr disklabel 8 ,
|
|
.Xr diskpart 8 ,
|
|
.Xr dumpfs 8 ,
|
|
.Xr fsck 8 ,
|
|
.Xr mount 8 ,
|
|
.Xr scsiformat 8 ,
|
|
.Xr tunefs 8 ,
|
|
.Xr vinum 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
|
|
command appeared in
|
|
.Bx 4.2 .
|