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NAME | SYNOPSIS | DESCRIPTION | FILES | SEE ALSO | NOTES | COLOPHON |
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xfs_fsr(8) System Manager's Manual xfs_fsr(8)
xfs_fsr - filesystem reorganizer for XFS
xfs_fsr [-vdg] [-t seconds] [-p passes] [-f leftoff] [-m mtab]
xfs_fsr [-vdg] [xfsdev | file] ...
xfs_fsr -V
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information found here is somehow inconsistent or out of date it is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 reorganize. 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.
/etc/mtab contains default list of filesystems to
reorganize.
/var/tmp/.fsrlast_xfs
records the state where reorganization left off.
xfs_fsr(8), mkfs.xfs(8), xfs_ncheck(8), xfs(5).
xfs_fsr 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 than 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.
xfs_fsr 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.
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 general 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.
This page is part of the xfsprogs (utilities for XFS filesystems)
project. Information about the project can be found at
⟨http://xfs.org/⟩. If you have a bug report for this manual page, see
⟨http://oss.sgi.com/bugzilla/buglist.cgi?product=XFS⟩. This page was
obtained from the project's upstream Git repository
⟨git://oss.sgi.com/xfs/cmds/xfsprogs⟩ on 2018-02-02. (At that time,
the date of the most recent commit that was found in the repository
was 2017-11-27.) If you discover any rendering problems in this HTML
version of the page, or you believe there is a better or more up-to-
date source for the page, or you have corrections or improvements to
the information in this COLOPHON (which is not part of the original
manual page), send a mail to man-pages@man7.org
xfs_fsr(8)
Pages that refer to this page: xfs_bmap(8)
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