47d3e2f83b
Make a note in the newfs.8 manual page to update the first backup superblock location when changing the default fragment size for the filesystem. Reported by: O. Hartmann
341 lines
11 KiB
Groff
341 lines
11 KiB
Groff
.\" Copyright (c) 1983, 1987, 1991, 1993, 1994
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)newfs.8 8.6 (Berkeley) 5/3/95
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.\" $FreeBSD$
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.\"
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.Dd January 29, 2019
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.Dt NEWFS 8
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.Os
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.Sh NAME
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.Nm newfs
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.Nd construct a new UFS1/UFS2 file system
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.Sh SYNOPSIS
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.Nm
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.Op Fl EJNUjlnt
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.Op Fl L Ar volname
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.Op Fl O Ar filesystem-type
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.Op Fl S Ar sector-size
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.Op Fl T Ar disktype
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.Op Fl a Ar maxcontig
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.Op Fl b Ar block-size
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.Op Fl c Ar blocks-per-cylinder-group
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.Op Fl d Ar max-extent-size
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.Op Fl e Ar maxbpg
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.Op Fl f Ar frag-size
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.Op Fl g Ar avgfilesize
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.Op Fl h Ar avgfpdir
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.Op Fl i Ar bytes
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.Op Fl k Ar held-for-metadata-blocks
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.Op Fl m Ar free-space
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.Op Fl o Ar optimization
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.Op Fl p Ar partition
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.Op Fl r Ar reserved
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.Op Fl s Ar size
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.Ar special
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.Sh DESCRIPTION
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The
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.Nm
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utility is used to initialize and clear file systems before first use.
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The
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.Nm
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utility builds a file system on the specified special file.
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(We often refer to the
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.Dq special file
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as the
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.Dq disk ,
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although the special file need not be a physical disk.
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In fact, it need not even be special.)
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Typically the defaults are reasonable, however
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.Nm
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has numerous options to allow the defaults to be selectively overridden.
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.Pp
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The following options define the general layout policies:
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.Bl -tag -width indent
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.It Fl E
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Erase the content of the disk before making the filesystem.
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The reserved area in front of the superblock (for bootcode) will not be erased.
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Erasing is only relevant to flash-memory or thinly provisioned devices.
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Erasing may take a long time.
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If the device does not support BIO_DELETE, the command will fail.
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.It Fl J
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Enable journaling on the new file system via gjournal.
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See
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.Xr gjournal 8
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for details.
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.It Fl L Ar volname
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Add a volume label to the new file system.
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Legal characters are alphanumerics, dashes, and underscores.
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.It Fl N
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Cause the file system parameters to be printed out
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without really creating the file system.
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.It Fl O Ar filesystem-type
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Use 1 to specify that a UFS1 format file system be built;
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use 2 to specify that a UFS2 format file system be built.
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The default format is UFS2.
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.It Fl T Ar disktype
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For backward compatibility.
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.It Fl U
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Enable soft updates on the new file system.
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.It Fl a Ar maxcontig
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Specify the maximum number of contiguous blocks that will be
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laid out before forcing a rotational delay.
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The default value is 16.
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See
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.Xr tunefs 8
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for more details on how to set this option.
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.It Fl b Ar block-size
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The block size of the file system, in bytes.
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It must be a power of 2.
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.\" If changing the default block size and it causes the default
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.\" fragment size to change, be sure to update the location of
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.\" the first backup superblock on the fsck_ffs.8 manual page.
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The
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default size is 32768 bytes, and the smallest allowable size is 4096 bytes.
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The optimal block:fragment ratio is 8:1.
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Other ratios are possible, but are not recommended,
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and may produce poor results.
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.It Fl c Ar blocks-per-cylinder-group
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The number of blocks per cylinder group in a file system.
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The default is to compute the maximum allowed by the other parameters.
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This value is
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dependent on a number of other parameters, in particular the block size
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and the number of bytes per inode.
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.It Fl d Ar max-extent-size
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The file system may choose to store large files using extents.
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This parameter specifies the largest extent size that may be used.
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The default value is the file system blocksize.
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It is presently limited to a maximum value of 16 times the
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file system blocksize and a minimum value of the file system blocksize.
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.It Fl e Ar maxbpg
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Indicate the maximum number of blocks any single file can
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allocate out of a cylinder group before it is forced to begin
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allocating blocks from another cylinder group.
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The default is about one quarter of the total blocks in a cylinder group.
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See
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.Xr tunefs 8
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for more details on how to set this option.
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.It Fl f Ar frag-size
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The fragment size of the file system in bytes.
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It must be a power of two
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ranging in value between
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.Ar blocksize Ns /8
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and
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.Ar blocksize .
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.\" If changing the default fragment size or it changes because of a
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.\" change to the default block size, be sure to update the location
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.\" of the first backup superblock on the fsck_ffs.8 manual page.
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The default is 4096 bytes.
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.It Fl g Ar avgfilesize
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The expected average file size for the file system.
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.It Fl h Ar avgfpdir
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The expected average number of files per directory on the file system.
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.It Fl i Ar bytes
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Specify the density of inodes in the file system.
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The default is to create an inode for every
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.Pq 2 * Ar frag-size
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bytes of data space.
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If fewer inodes are desired, a larger number should be used;
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to create more inodes a smaller number should be given.
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One inode is required for each distinct file, so this value effectively
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specifies the average file size on the file system.
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.It Fl j
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Enable soft updates journaling on the new file system.
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This flag is implemented by running the
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.Xr tunefs 8
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utility found in the user's
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.Dv $PATH .
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.It Fl k Ar held-for-metadata-blocks
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Set the amount of space to be held for metadata blocks in each cylinder group.
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When set, the file system preference routines will try to save
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the specified amount of space immediately following the inode blocks
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in each cylinder group for use by metadata blocks.
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Clustering the metadata blocks speeds up random file access
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and decreases the running time of
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.Xr fsck 8 .
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By default
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.Nm
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sets it to half of the space reserved to minfree.
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.It Fl l
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Enable multilabel MAC on the new file system.
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.It Fl m Ar free-space
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The percentage of space reserved from normal users; the minimum free
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space threshold.
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The default value used is
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defined by
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.Dv MINFREE
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from
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.In ufs/ffs/fs.h ,
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currently 8%.
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See
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.Xr tunefs 8
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for more details on how to set this option.
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.It Fl n
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Do not create a
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.Pa .snap
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directory on the new file system.
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The resulting file system will not support snapshot generation, so
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.Xr dump 8
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in live mode and background
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.Xr fsck 8
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will not function properly.
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The traditional
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.Xr fsck 8
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and offline
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.Xr dump 8
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will work on the file system.
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This option is intended primarily for memory or vnode-backed file systems that
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do not require
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.Xr dump 8
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or
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.Xr fsck 8
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support.
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.It Fl o Ar optimization
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.Cm ( space
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or
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.Cm time ) .
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The file system can either be instructed to try to minimize the time spent
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allocating blocks, or to try to minimize the space fragmentation on the disk.
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If the value of minfree (see above) is less than 8%,
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the default is to optimize for
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.Cm space ;
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if the value of minfree is greater than or equal to 8%,
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the default is to optimize for
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.Cm time .
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See
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.Xr tunefs 8
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for more details on how to set this option.
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.It Fl p Ar partition
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The partition name (a..h) you want to use in case the underlying image
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is a file, so you do not have access to individual partitions through the
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filesystem.
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Can also be used with a device, e.g.,
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.Nm
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.Fl p Ar f
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.Ar /dev/da1s3
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is equivalent to
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.Nm
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.Ar /dev/da1s3f .
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.It Fl r Ar reserved
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The size, in sectors, of reserved space
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at the end of the partition specified in
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.Ar special .
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This space will not be occupied by the file system;
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it can be used by other consumers such as
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.Xr geom 4 .
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Defaults to 0.
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.It Fl s Ar size
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The size of the file system in sectors.
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This value defaults to the size of the
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raw partition specified in
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.Ar special
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less the
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.Ar reserved
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space at its end (see
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.Fl r ) .
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A
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.Ar size
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of 0 can also be used to choose the default value.
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A valid
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.Ar size
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value cannot be larger than the default one,
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which means that the file system cannot extend into the reserved space.
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.It Fl t
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Turn on the TRIM enable flag.
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If enabled, and if the underlying device supports the BIO_DELETE
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command, the file system will send a delete request to the underlying
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device for each freed block.
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The trim enable flag is typically set for flash-memory devices to
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reduce write amplification which reduces wear on write-limited
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flash-memory and often improves long-term performance.
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Thinly provisioned storage also benefits by returning unused blocks to
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the global pool.
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.El
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.Pp
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The following options override the standard sizes for the disk geometry.
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Their default values are taken from the disk label.
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Changing these defaults is useful only when using
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.Nm
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to build a file system whose raw image will eventually be used on a
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different type of disk than the one on which it is initially created
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(for example on a write-once disk).
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Note that changing any of these values from their defaults will make
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it impossible for
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.Xr fsck 8
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to find the alternate superblocks if the standard superblock is lost.
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.Bl -tag -width indent
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.It Fl S Ar sector-size
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The size of a sector in bytes (almost never anything but 512).
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.El
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.Sh EXAMPLES
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.Dl newfs /dev/ada3s1a
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.Pp
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Creates a new ufs file system on
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.Pa ada3s1a .
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The
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.Nm
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utility will use a block size of 32768 bytes, a fragment size of 4096 bytes
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and the largest possible number of blocks per cylinders group.
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These values tend to produce better performance for most applications
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than the historical defaults
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(8192 byte block size and 1024 byte fragment size).
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This large fragment size may lead to much wasted space
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on file systems that contain many small files.
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.Sh SEE ALSO
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.Xr fdformat 1 ,
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.Xr geom 4 ,
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.Xr disktab 5 ,
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.Xr fs 5 ,
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.Xr camcontrol 8 ,
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.Xr dump 8 ,
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.Xr dumpfs 8 ,
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.Xr fsck 8 ,
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.Xr gpart 8 ,
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.Xr gjournal 8 ,
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.Xr growfs 8 ,
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.Xr gvinum 8 ,
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.Xr makefs 8 ,
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.Xr mount 8 ,
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.Xr tunefs 8
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.Rs
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.%A M. McKusick
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.%A W. Joy
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.%A S. Leffler
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.%A R. Fabry
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.%T A Fast File System for UNIX
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.%J ACM Transactions on Computer Systems 2
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.%V 3
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.%P pp 181-197
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.%D August 1984
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.%O (reprinted in the BSD System Manager's Manual)
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.Re
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.Sh HISTORY
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The
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.Nm
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utility appeared in
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.Bx 4.2 .
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