1.\" $NetBSD: lfs_cleanerd.8,v 1.12 2002/09/29 14:05:54 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. All advertising materials mentioning features or use of this software 15.\" must display the following acknowledgement: 16.\" This product includes software developed by the University of 17.\" California, Berkeley and its contributors. 18.\" 4. Neither the name of the University nor the names of its contributors 19.\" may be used to endorse or promote products derived from this software 20.\" without specific prior written permission. 21.\" 22.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32.\" SUCH DAMAGE. 33.\" 34.\" from: @(#)lfs_cleanerd.8 8.2 (Berkeley) 12/11/93 35.\" 36.Dd December 11, 1993 37.Dt LFS_CLEANERD 8 38.Os 39.Sh NAME 40.Nm lfs_cleanerd 41.Nd garbage collect a log-structured file system 42.Sh SYNOPSIS 43.Nm 44.Op Fl bcdfmqs 45.Op Fl l Ar load-threshhold 46.Op Fl n Ar number-of-segments 47.Op Fl r Ar report-frequency 48.Op Fl t Ar timeout 49.Pa node 50.Sh DESCRIPTION 51The 52.Nm 53command starts a daemon process which garbage-collects 54the log-structured file system residing at the point named by 55.Ar node 56in the global file system namespace. 57This command is normally executed by 58.Xr mount_lfs 8 59when the log-structured file system is mounted. 60The daemon will exit within a few minutes 61of when the file system it was cleaning is unmounted. 62.Pp 63Garbage collection on a log-structured file system is done by scanning 64the file system's segments for active, i.e. referenced, data and copying 65it to new segments. 66When all of the active data in a given segment has been copied to a new 67segment that segment can be marked as empty, thus reclaiming the space 68taken by the inactive data which was in it. 69.Pp 70The following options are available: 71.Bl -tag -width indent 72.It Fl b 73Use bytes written, rather than segments read, when determining how many 74segments to clean at once. 75.It Fl c 76Coalescing mode. 77For each live inode, check to see if it has too many 78blocks that are not contiguous, and if it does, rewrite it. 79After a single pass through the filesystem the cleaner will exit. 80.It Fl d 81Run in debug mode. 82Do not become a daemon process, and print debugging information. 83More 84.Fl d 85s give more detailed debugging information. 86.It Fl f 87Use filesystem idle time as the criterion for aggressive cleaning, 88instead of system load. 89.It Fl l Ar load-threshhold 90Clean more aggressively when the system load is below the given threshhold. 91The default threshhold is 0.2. 92.It Fl m 93Use mmap, rather than rereading the Ifile to update the cleaner's 94knowledge of the filesystem. 95Do not use this option. 96.It Fl n Ar number-of-segments 97Clean this number of segments at a time: that is, pass this many 98segments' blocks through a single call to lfs_markv, or, if 99.Fl b 100was also given, pass this many segments' worth of blocks through a 101single call to lfs_markv. 102.It Fl q 103Quit after cleaning once. 104.It Fl r Ar report-frequency 105Give an efficiency report after every 106.Ar report-frequency 107times through the main loop. 108.It Fl s 109When cleaning the file system, 110send only a few blocks through lfs_markv at a time. 111Don't use this option. 112.It Fl t Ar timeout 113Poll the filesystem every 114.Ar timeout 115seconds, looking for opportunities to clean. 116The default is 300, that is, five minutes. 117Note that 118.Nm 119will be automatically awakened when the filesystem is active, 120so it is not usually necessary to set 121.Ar timeout 122to a low value. 123.El 124.Sh SEE ALSO 125.Xr lfs_bmapv 2 , 126.Xr lfs_markv 2 , 127.Xr lfs_segwait 2 , 128.Xr mount_lfs 8 129.Sh HISTORY 130The 131.Nm 132utility first appeared in 133.Bx 4.4 . 134