xfs_fsr(8) System Manager's Manual xfs_fsr(8)
NAME
xfs_fsr - filesystem reorganizer for XFS
SYNOPSIS
xfs_fsr [-vdg] [-t seconds] [-p passes] [-f leftoff] [-m mtab]
xfs_fsr [-vdg] [xfsdev | file] ...
xfs_fsr -V
DESCRIPTION
xfs_fsr is applicable only to XFS filesystems.
xfs_fsr 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 xfs_fsr. 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.
-t seconds How long to reorganize. The default is 7200 seconds (2 hours).
-p passes Number of passes before terminating global re-org. The default is 10 passes.
-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.
-d Debug. Print even more cryptic information.
-g Print to syslog (default if stdout not a tty).
-V Prints the version number and exits.
When invoked with no arguments xfs_fsr reorganizes all regular files in all mounted filesystems. xfs_fsr
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somehow inconsistent or out of date it is ignored and reorganization starts at the beginning of the first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.
xfs_fsr can be called with one or more arguments naming filesystems (block device name), and files to reorga‐
nize. In this mode xfs_fsr 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 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
/etc/mtab contains default list of filesystems to reorganize.
/var/tmp/.fsrlast_xfs
records the state where reorganization left off.
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 tempo‐
rary files are unlinked upon creation so data will not be readable by any other process.
xfs_fsr 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.
Files marked as no-defrag will be skipped. The xfs_io(8) chattr command with the f attribute can be used to
set or clear this flag. Files and directories created in a directory with the no-defrag flag will inherit the
attribute.
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 xfs_fsr skips the filesystem described by that line. See
the fstab(5) reference page for more details.
In general we do not foresee the need to run xfs_fsr on system partitions such as /, /boot and /usr as in gen‐
eral these will not suffer from fragmentation. There are also issues with defragmenting files lilo(8) uses to
boot your system. It is recommended that these files should be flagged as no-defrag with the xfs_io(8) chattr
command. Should these files be moved by xfs_fsr then you must rerun lilo before you reboot or you may have an
unbootable system.
xfs_fsr(8)
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