1.\" $NetBSD: lfs_cleanerd.8,v 1.18 2009/08/06 21:18:54 wiz Exp $ 2.\" 3.\" Copyright (c) 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.\" from: @(#)lfs_cleanerd.8 8.2 (Berkeley) 12/11/93 31.\" 32.Dd August 6, 2009 33.Dt LFS_CLEANERD 8 34.Os 35.Sh NAME 36.Nm lfs_cleanerd 37.Nd garbage collect a log-structured file system 38.Sh SYNOPSIS 39.Nm 40.Op Fl bcDdfmqs 41.Op Fl i Ar segment-number 42.Op Fl l Ar load-threshhold 43.Op Fl n Ar number-of-segments 44.Op Fl r Ar report-frequency 45.Op Fl t Ar timeout 46.Pa node 47.Sh DESCRIPTION 48The 49.Nm 50command starts a daemon process which garbage-collects 51the log-structured file system residing at the point named by 52.Ar node 53in the global file system namespace. 54This command is normally executed by 55.Xr mount_lfs 8 56when the log-structured file system is mounted. 57The daemon will exit within a few minutes 58of when the file system it was cleaning is unmounted. 59.Pp 60Garbage collection on a log-structured file system is done by scanning 61the file system's segments for active, i.e. referenced, data and copying 62it to new segments. 63When all of the active data in a given segment has been copied to a new 64segment that segment can be marked as empty, thus reclaiming the space 65taken by the inactive data which was in it. 66.Pp 67The following options are available: 68.Bl -tag -width indent 69.It Fl b 70Use bytes written, rather than segments read, when determining how many 71segments to clean at once. 72.It Fl c 73Coalescing mode. 74For each live inode, check to see if it has too many 75blocks that are not contiguous, and if it does, rewrite it. 76After a single pass through the filesystem the cleaner will exit. 77This option has been reported to corrupt file data; do not use it. 78.It Fl D 79Stay in the foreground, do not become a daemon process. 80Does not print additional debugging information (in contrast to 81.Fl d ) . 82.It Fl d 83Run in debug mode. 84Do not become a daemon process, and print debugging information. 85More 86.Fl d 87s give more detailed debugging information. 88.It Fl f 89Use filesystem idle time as the criterion for aggressive cleaning, 90instead of system load. 91.It Fl i Ar segment-number 92Invalidate the segment with segment number 93.Ar segment-number . 94This option is used by 95.Xr resize_lfs 8 , 96and should not be specified on the command line. 97.It Fl l Ar load-threshhold 98Clean more aggressively when the system load is below the given threshhold. 99The default threshhold is 0.2. 100.It Fl m 101Does nothing. 102This option is present for historical compatibility. 103.It Fl n Ar number-of-segments 104Clean this number of segments at a time: that is, pass this many 105segments' blocks through a single call to lfs_markv, or, if 106.Fl b 107was also given, pass this many segments' worth of blocks through a 108single call to lfs_markv. 109.It Fl q 110Quit after cleaning once. 111.It Fl r Ar report-frequency 112Give an efficiency report after every 113.Ar report-frequency 114times through the main loop. 115.It Fl s 116When cleaning the file system, 117send only a few blocks through lfs_markv at a time. 118Don't use this option. 119.It Fl t Ar timeout 120Poll the filesystem every 121.Ar timeout 122seconds, looking for opportunities to clean. 123The default is 300, that is, five minutes. 124Note that 125.Nm 126will be automatically awakened when the filesystem is active, 127so it is not usually necessary to set 128.Ar timeout 129to a low value. 130.El 131.Sh SEE ALSO 132.Xr lfs_bmapv 2 , 133.Xr lfs_markv 2 , 134.Xr lfs_segwait 2 , 135.Xr mount_lfs 8 136.Sh HISTORY 137The 138.Nm 139utility first appeared in 140.Bx 4.4 . 141