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lfs_cleanerd(8) [netbsd man page]

LFS_CLEANERD(8) 					    BSD System Manager's Manual 					   LFS_CLEANERD(8)

NAME
lfs_cleanerd -- garbage collect a log-structured file system SYNOPSIS
lfs_cleanerd [-bcDdfmqs] [-i segment-number] [-l load-threshhold] [-n number-of-segments] [-r report-frequency] [-t timeout] node DESCRIPTION
The lfs_cleanerd command starts a daemon process which garbage-collects the log-structured file system residing at the point named by node in the global file system namespace. This command is normally executed by mount_lfs(8) when the log-structured file system is mounted. The daemon will exit within a few minutes of when the file system it was cleaning is unmounted. Garbage collection on a log-structured file system is done by scanning the file system's segments for active, i.e. referenced, data and copy- ing it to new segments. When all of the active data in a given segment has been copied to a new segment that segment can be marked as empty, thus reclaiming the space taken by the inactive data which was in it. The following options are available: -b Use bytes written, rather than segments read, when determining how many segments to clean at once. -c Coalescing mode. For each live inode, check to see if it has too many blocks that are not contiguous, and if it does, rewrite it. After a single pass through the filesystem the cleaner will exit. This option has been reported to corrupt file data; do not use it. -D Stay in the foreground, do not become a daemon process. Does not print additional debugging information (in contrast to -d). -d Run in debug mode. Do not become a daemon process, and print debugging information. More -d s give more detailed debugging informa- tion. -f Use filesystem idle time as the criterion for aggressive cleaning, instead of system load. -i segment-number Invalidate the segment with segment number segment-number. This option is used by resize_lfs(8), and should not be specified on the command line. -l load-threshhold Clean more aggressively when the system load is below the given threshhold. The default threshhold is 0.2. -m Does nothing. This option is present for historical compatibility. -n number-of-segments Clean this number of segments at a time: that is, pass this many segments' blocks through a single call to lfs_markv, or, if -b was also given, pass this many segments' worth of blocks through a single call to lfs_markv. -q Quit after cleaning once. -r report-frequency Give an efficiency report after every report-frequency times through the main loop. -s When cleaning the file system, send only a few blocks through lfs_markv at a time. Don't use this option. -t timeout Poll the filesystem every timeout seconds, looking for opportunities to clean. The default is 300, that is, five minutes. Note that lfs_cleanerd will be automatically awakened when the filesystem is active, so it is not usually necessary to set timeout to a low value. SEE ALSO
lfs_bmapv(2), lfs_markv(2), lfs_segwait(2), mount_lfs(8) HISTORY
The lfs_cleanerd utility first appeared in 4.4BSD. BSD
August 6, 2009 BSD

Check Out this Related Man Page

IPCS(1) 						    BSD General Commands Manual 						   IPCS(1)

NAME
ipcs -- report System V interprocess communication facilities status SYNOPSIS
ipcs [-abcMmopQqSsTt] DESCRIPTION
The ipcs utility provides information on System V interprocess communication (IPC) facilities on the system. The options are as follows: -a Show the maximum amount of information possible when displaying active semaphores, message queues, and shared memory segments. (This is shorthand for specifying the -b, -c, -o, -p, and -t options.) -b Show the maximum allowed sizes for active semaphores, message queues, and shared memory segments. The ``maximum allowed size'' is the maximum number of bytes in a message on a message queue, the size of a shared memory segment, or the number of semaphores in a set of semaphores. -c Show the creator's name and group for active semaphores, message queues, and shared memory segments. -M Display system information about shared memory. -m Display information about active shared memory segments. -o Show outstanding usage for active message queues, and shared memory segments. The ``outstanding usage'' is the number of messages in a message queue, or the number of processes attached to a shared memory segment. -p Show the process ID information for active semaphores, message queues, and shared memory segments. The ``process ID information'' is the last process to send a message to or receive a message from a message queue, the process that created a semaphore, or the last process to attach or detach a shared memory segment. -Q Display system information about messages queues. -q Display information about active message queues. -S Display system information about semaphores. -s Display information about active semaphores. -T Display system information about shared memory, message queues and semaphores. -t Show access times for active semaphores, message queues, and shared memory segments. The access times is the time of the last con- trol operation on an IPC object, the last send or receive of a message, the last attach or detach of a shared memory segment, or the last operation on a semaphore. If none of the -M, -m, -Q, -q, -S, or -s options are specified, information about all active IPC facilities is listed. RESTRICTIONS
System data structures may change while ipcs is running; the output of ipcs is not guaranteed to be consistent. BUGS
This manual page is woefully incomplete, because it does not at all attempt to explain the information printed by ipcs. SEE ALSO
ipcrm(1) AUTHORS
Thorsten Lockert <tholo@sigmasoft.com> BSD
June 18, 1994 BSD
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