fsr_xfs(1M)							   fsr_xfs(1M)

NAME    [Toc]    [Back]

     fsr_xfs - filesystem reorganizer for XFS

SYNOPSIS    [Toc]    [Back]

     /usr/etc/fsr_xfs [-v] [-t seconds]	[-f leftoff] [-m mtab]
     /usr/etc/fsr_xfs [-v] [xfsdev | file] ...

DESCRIPTION    [Toc]    [Back]

     fsr_xfs is	applicable only	to XFS filesystems.

     fsr_xfs improves the organization of mounted filesystems.	The
     reorganization algorithm operates on one file at a	time, compacting or
     otherwise improving the layout of the file	extents	(contiguous blocks of
     file data).

     The following options are accepted	by fsr_xfs.  The -m, -t, and -f
     options have no meaning if	any filesystems	or files are specified on the
     command line.

     -m	mtab	  Use this file	for the	list of	filesystems to reorganize.
		  The default is to use	/etc/mtab.  This file must be in
		  mtab(4) format.

     -t	seconds	  How long to reorganize.  The default is 7200 (2 hours).

     -f	leftoff	  Use this file	instead	of /var/tmp/.fsrlast to	read the state
		  of where to start and	as the file to store the state of
		  where	reorganization left off.

     -v		  Verbose.  Print cryptic information about each file being
		  reorganized.

     The intended usage	is to regularly	run the	fsr command which in turn
     invokes fsr_xfs when it encounters	XFS filesystems.  By default this is
     done from crontab once per	week.

     When invoked with no arguments fsr_xfs reorganizes	all regular files in
     all mounted filesystems.  fsr_xfs makes many cycles over /etc/mtab	each
     time making a single pass over each XFS filesystem.  Each pass goes
     through and selects files that have the largest number of extents.	 It
     attempts to defragment the	top 10%	of these files on each pass.

     It	runs for up to two hours after which it	records	the filesystem where
     it	left off, so it	can start there	the next time.	This information is
     stored in the file	/var/tmp/.fsrlast_xfs. If the information found	here
     is	somehow	inconsistent or	out of date it is ignored and reorganization
     starts at the beginning of	the first filesystem found in /etc/mtab.

     fsr_xfs can be called with	one or more arguments naming filesystems
     (block device name), and files to reorganize.  In this mode fsr_xfs does
     not read or write /var/tmp/.fsrlast_xfs nor does it run for a fixed time
     interval.	It makes one pass through each specified regular file and all



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fsr_xfs(1M)							   fsr_xfs(1M)



     regular files in each specified filesystem.  A command line name
     referring to a symbolic link (except to a file system device), FIFO, or
     UNIX domain socket	generates a warning message, but is otherwise ignored.
     While traversing the filesystem these types of files are silently
     skipped.

FILES    [Toc]    [Back]

     /etc/mtab		  contains default list	of filesystems to reorganize.
     /var/tmp/.fsrlast_xfs
			  records the state where reorganization left off.

SEE ALSO    [Toc]    [Back]

     fsr(1M), mkfs_xfs(1M), mtab(4), xfs_ncheck(1M), xfs(4).

NOTES    [Toc]    [Back]

     fsr_xfs improves the layout of extents for	each file by copying the
     entire file to a temporary	location and then interchanging	the data
     extents of	the target and temporary files in an atomic manner. This
     method requires that enough free disk space be available to copy any
     given file	and that the space be less fragmented then the original	file.
     It	also requires the owner	of the file to have enough remaining filespace
     quota to do the copy on systems running quotas.  fsr_xfs generates	a
     warning message if	space is not sufficient	to improve the target file.

     A temporary file used in improving	a file given on	the command line is
     created in	the same parent	directory of the target	file and is prefixed
     by	the string '.fsr'. The temporary files used in improving an entire XFS
     device are	stored in a directory at the root of the target	device and use
     the same naming scheme.  The temporary files are unlinked upon creation
     so	data will not be readable by any other process.

     fsr_xfs does not operate on files that are	currently mapped in memory.  A
     'file busy' error can be seen for these files if the verbose flag (-v) is
     set.

     An	entry in /etc/mtab or the file specified using the -m option must have
     the rw option specified for read and write	access.	 If this option	is not
     present, then fsr_xfs skips the filesystem	described by that line.	 See
     the fsta
 reference	pages for more details.


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