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 copying 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:
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-b
-
Use bytes written, rather than segments read, when determining how many segments to clean at once.
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-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.
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-D
-
Stay in the foreground, do not become a daemon process. Does not print additional debugging information (in contrast to -d).
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-d
-
Run in debug mode. Do not become a daemon process, and print debugging information. More -d s give more detailed debugging information.
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-f
-
Use filesystem idle time as the criterion for aggressive cleaning, instead of system load.
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-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.
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-l load-threshhold
-
Clean more aggressively when the system load is below the given threshhold. The default threshhold is 0.2.
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-m
-
Does nothing. This option is present for historical compatibility.
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-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.
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-q
-
Quit after cleaning once.
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-r report-frequency
-
Give an efficiency report after every report-frequency times through the main loop.
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-s
-
When cleaning the file system, send only a few blocks through lfs_markv at a time. Don't use this option.
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-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.
