Annotation of wikisrc/users/schmonz/tunefs.8, revision 1.1

1.1     ! schmonz     1: .\"    $NetBSD: tunefs.8,v 1.38 2009/02/22 20:28:05 ad Exp $
        !             2: .\"
        !             3: .\" Copyright (c) 1983, 1991, 1993
        !             4: .\"    The Regents of the University of California.  All rights reserved.
        !             5: .\"
        !             6: .\" Redistribution and use in source and binary forms, with or without
        !             7: .\" modification, are permitted provided that the following conditions
        !             8: .\" are met:
        !             9: .\" 1. Redistributions of source code must retain the above copyright
        !            10: .\"    notice, this list of conditions and the following disclaimer.
        !            11: .\" 2. Redistributions in binary form must reproduce the above copyright
        !            12: .\"    notice, this list of conditions and the following disclaimer in the
        !            13: .\"    documentation and/or other materials provided with the distribution.
        !            14: .\" 3. Neither the name of the University nor the names of its contributors
        !            15: .\"    may be used to endorse or promote products derived from this software
        !            16: .\"    without specific prior written permission.
        !            17: .\"
        !            18: .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
        !            19: .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
        !            20: .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
        !            21: .\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
        !            22: .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
        !            23: .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
        !            24: .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
        !            25: .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
        !            26: .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
        !            27: .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
        !            28: .\" SUCH DAMAGE.
        !            29: .\"
        !            30: .\"     @(#)tunefs.8   8.3 (Berkeley) 5/3/95
        !            31: .\"
        !            32: .Dd April 26, 2004
        !            33: .Dt TUNEFS 8
        !            34: .Os
        !            35: .Sh NAME
        !            36: .Nm tunefs
        !            37: .Nd tune up an existing file system
        !            38: .Sh SYNOPSIS
        !            39: .Nm
        !            40: .Op Fl AFN
        !            41: .Op Fl e Ar maxbpg
        !            42: .Op Fl g Ar avgfilesize
        !            43: .Op Fl h Ar avgfpdir
        !            44: .Op Fl l Ar logsize
        !            45: .Op Fl m Ar minfree
        !            46: .Bk -words
        !            47: .Op Fl o Ar optimize_preference
        !            48: .Ek
        !            49: .Ar special | Ar filesys
        !            50: .Sh DESCRIPTION
        !            51: .Nm
        !            52: is designed to change the dynamic parameters of a file system
        !            53: which affect the layout policies.
        !            54: .Pp
        !            55: The following options are supported by
        !            56: .Nm :
        !            57: .Bl -tag -width Ds
        !            58: .It Fl A
        !            59: Cause the values to be updated in all the alternate
        !            60: superblocks instead of just the standard superblock.
        !            61: If this option is not used,
        !            62: then use of a backup superblock by
        !            63: .Xr fsck 8
        !            64: will lose anything changed by
        !            65: .Nm .
        !            66: .Fl A
        !            67: is ignored when
        !            68: .Fl N
        !            69: is specified.
        !            70: .It Fl F
        !            71: Indicates that
        !            72: .Ar special
        !            73: is a file system image, rather than a device name or file system mount point.
        !            74: .Ar special
        !            75: will be accessed
        !            76: .Sq as-is .
        !            77: .It Fl N
        !            78: Display all the settable options
        !            79: (after any changes from the tuning options)
        !            80: but do not cause any of them to be changed.
        !            81: .It Fl e Ar maxbpg
        !            82: This indicates the maximum number of blocks any single file can
        !            83: allocate out of a cylinder group before it is forced to begin
        !            84: allocating blocks from another cylinder group.
        !            85: Typically this value is set to about one quarter of the total blocks
        !            86: in a cylinder group.
        !            87: The intent is to prevent any single file from using up all the
        !            88: blocks in a single cylinder group,
        !            89: thus degrading access times for all files subsequently allocated
        !            90: in that cylinder group.
        !            91: The effect of this limit is to cause big files to do long seeks
        !            92: more frequently than if they were allowed to allocate all the blocks
        !            93: in a cylinder group before seeking elsewhere.
        !            94: For file systems with exclusively large files,
        !            95: this parameter should be set higher.
        !            96: .It Fl g Ar avgfilesize
        !            97: This specifies the expected average file size.
        !            98: .It Fl h Ar avgfpdir
        !            99: This specifies the expected number of files per directory.
        !           100: .It Fl l Ar logsize
        !           101: This value specifies the size of the in-filesystem journaling log file.
        !           102: The default journaling log file size is described in
        !           103: .Xr wapbl 4 .
        !           104: Specifying a size of zero will cause the in-filesystem journaling log file
        !           105: to be removed the next time the filesystem is mounted.
        !           106: The size of an existing in-filesystem journaling log file can not be changed.
        !           107: .It Fl m Ar minfree
        !           108: This value specifies the percentage of space held back
        !           109: from normal users; the minimum free space threshold.
        !           110: The default value is set during creation of the filesystem, see
        !           111: .Xr newfs 8 .
        !           112: This value can be set to zero, however up to a factor of three
        !           113: in throughput will be lost over the performance obtained at a 5%
        !           114: threshold.
        !           115: Note that if the value is raised above the current usage level,
        !           116: users will be unable to allocate files until enough files have
        !           117: been deleted to get under the higher threshold.
        !           118: .It Fl o Ar optimize_preference
        !           119: The file system can either try to minimize the time spent
        !           120: allocating blocks, or it can attempt to minimize the space
        !           121: fragmentation on the disk.
        !           122: If the value of minfree (see above) is less than 5%,
        !           123: then the file system should optimize for space to avoid
        !           124: running out of full sized blocks.
        !           125: For values of minfree greater than or equal to 5%,
        !           126: fragmentation is unlikely to be problematical, and
        !           127: the file system can be optimized for time.
        !           128: .Pp
        !           129: .Ar optimize_preference
        !           130: can be specified as either
        !           131: .Li space
        !           132: or
        !           133: .Li time .
        !           134: .El
        !           135: .Sh SEE ALSO
        !           136: .Xr wapbl 4 ,
        !           137: .Xr fs 5 ,
        !           138: .Xr dumpfs 8 ,
        !           139: .Xr fsck_ffs 8 ,
        !           140: .Xr newfs 8
        !           141: .Rs
        !           142: .%A M. McKusick
        !           143: .%A W. Joy
        !           144: .%A S. Leffler
        !           145: .%A R. Fabry
        !           146: .%T "A Fast File System for UNIX"
        !           147: .%J "ACM Transactions on Computer Systems 2"
        !           148: .%N 3
        !           149: .%P pp 181-197
        !           150: .%D August 1984
        !           151: .%O "(reprinted in the BSD System Manager's Manual, SMM:5)"
        !           152: .Re
        !           153: .Sh HISTORY
        !           154: The
        !           155: .Nm
        !           156: command appeared in
        !           157: .Bx 4.2 .
        !           158: .Sh BUGS
        !           159: This program should work on mounted and active file systems.
        !           160: Because the super-block is not kept in the buffer cache,
        !           161: the changes will only take effect if the program
        !           162: is run on unmounted file systems.
        !           163: To change the root file system, the system must be rebooted
        !           164: after the file system is tuned.
        !           165: .Pp
        !           166: .\" Take this out and a Unix Demon will dog your steps from now until
        !           167: .\" the time_t's wrap around.
        !           168: You can tune a file system, but you can't tune a fish.

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