xfs_fsr(8) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | FILES | SEE ALSO | NOTES | COLOPHON

xfs_fsr(8)               System Manager's Manual              xfs_fsr(8)

NAME         top

       xfs_fsr - filesystem reorganizer for XFS

SYNOPSIS         top

       xfs_fsr [-vdg] [-t seconds] [-p passes] [-f leftoff] [-m mtab]
       xfs_fsr [-vdg] [xfsdev | file] ...
       xfs_fsr -V

DESCRIPTION         top

       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       information found here is somehow inconsistent or out of date it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.

FILES         top

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

SEE ALSO         top

       xfs_fsr(8), mkfs.xfs(8), xfs_ncheck(8), xfs(5).

NOTES         top

       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.

COLOPHON         top

       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,
       send it to linux-xfs@vger.kernel.org.  This page was obtained
       from the project's upstream Git repository
       ⟨https://git.kernel.org/pub/scm/fs/xfs/xfsprogs-dev.git⟩ on
       2021-06-20.  (At that time, the date of the most recent commit
       that was found in the repository was 2021-05-21.)  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)xfs_fsr(8)