1.\" $NetBSD: lfs_cleanerd.8,v 1.21 2021/07/31 15:02:54 andvar 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 J Ar raw-device 43.Op Fl l Ar load-threshold 44.Op Fl n Ar number-of-segments 45.Op Fl r Ar report-frequency 46.Op Fl S Ar semaphore-address 47.Op Fl t Ar timeout 48.Pa node 49.Sh DESCRIPTION 50The 51.Nm 52command starts a daemon process which garbage-collects 53the log-structured file system residing at the point named by 54.Ar node 55in the global file system namespace. 56This command is normally executed by 57.Xr mount_lfs 8 58when the log-structured file system is mounted. 59The daemon will exit within a few minutes 60of when the file system it was cleaning is unmounted. 61.Pp 62Garbage collection on a log-structured file system is done by scanning 63the file system's segments for active, i.e. referenced, data and copying 64it to new segments. 65When all of the active data in a given segment has been copied to a new 66segment that segment can be marked as empty, thus reclaiming the space 67taken by the inactive data which was in it. 68.Pp 69The following options are available: 70.Bl -tag -width indent 71.It Fl b 72Use bytes written, rather than segments read, when determining how many 73segments to clean at once. 74.It Fl c 75Coalescing mode. 76For each live inode, check to see if it has too many 77blocks that are not contiguous, and if it does, rewrite it. 78After a single pass through the filesystem the cleaner will exit. 79This option has been reported to corrupt file data; do not use it. 80.It Fl D 81Stay in the foreground, do not become a daemon process. 82Does not print additional debugging information (in contrast to 83.Fl d ) . 84.It Fl d 85Run in debug mode. 86Do not become a daemon process, and print debugging information. 87More 88.Fl d 89s give more detailed debugging information. 90.It Fl f 91Use filesystem idle time as the criterion for aggressive cleaning, 92instead of system load. 93.It Fl i Ar segment-number 94Invalidate the segment with segment number 95.Ar segment-number . 96This option is used by 97.Xr resize_lfs 8 , 98and should not be specified on the command line. 99.It Fl J Ar raw device 100Specify the raw device that the cleaner is to work against rather than 101trying to figure it out from the mount point. 102This is mostly useful when the cleaner is compiled into 103.Xr rump_lfs 8 104and the ATF test framework. 105.It Fl l Ar load-threshold 106Clean more aggressively when the system load is below the given threshold. 107The default threshold is 0.2. 108.It Fl m 109Does nothing. 110This option is present for historical compatibility. 111.It Fl n Ar number-of-segments 112Clean this number of segments at a time: that is, pass this many 113segments' blocks through a single call to lfs_markv, or, if 114.Fl b 115was also given, pass this many segments' worth of blocks through a 116single call to lfs_markv. 117.It Fl q 118Quit after cleaning once. 119.It Fl r Ar report-frequency 120Give an efficiency report after every 121.Ar report-frequency 122times through the main loop. 123.It Fl S Ar semaphore address 124When the cleaner code is compiled into 125.Xr rump_lfs 8 126and the ATF frame work, this option allows for a synchronization 127semaphore to be specified. 128This option is not available in the stand-alone 129.Nm . 130.It Fl s 131When cleaning the file system, 132send only a few blocks through lfs_markv at a time. 133Don't use this option. 134.It Fl t Ar timeout 135Poll the filesystem every 136.Ar timeout 137seconds, looking for opportunities to clean. 138The default is 300, that is, five minutes. 139Note that 140.Nm 141will be automatically awakened when the filesystem is active, 142so it is not usually necessary to set 143.Ar timeout 144to a low value. 145.El 146.Sh SEE ALSO 147.Xr lfs_bmapv 2 , 148.Xr lfs_markv 2 , 149.Xr lfs_segwait 2 , 150.Xr mount_lfs 8 , 151.Xr rump_lfs 8 152.Sh HISTORY 153The 154.Nm 155utility first appeared in 156.Bx 4.4 . 157