xfs_admin(8) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | OPTIONS | SEE ALSO | COLOPHON

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

NAME         top

       xfs_admin - change parameters of an XFS filesystem

SYNOPSIS         top

       xfs_admin [ -eflpu ] [ -O featurelist ] [ -c 0|1 ] [ -L label ] [
       -U uuid ] [ -r rtdev ] device [ logdev ]
       xfs_admin -V

DESCRIPTION         top

       xfs_admin uses the xfs_db(8) command to modify various parameters
       of a filesystem.

       Devices that are mounted cannot be modified.  Administrators must
       unmount filesystems before xfs_admin or xfs_db(8) can convert
       parameters.  A number of parameters of a mounted filesystem can
       be examined and modified using the xfs_growfs(8) command.

       The optional logdev parameter specifies the device special file
       where the filesystem's external log resides.  This is required
       only for filesystems that use an external log.  See the mkfs.xfs
       -l option, and refer to xfs(5) for a detailed description of the
       XFS log.

OPTIONS         top

       -e     Enables unwritten extent support on a filesystem that does
              not already have this enabled (for legacy filesystems, it
              can't be disabled anymore at mkfs time).

              This option only applies to the deprecated V4 format.

       -f     Specifies that the filesystem image to be processed is
              stored in a regular file at device (see the mkfs.xfs -d
              file option).

       -j     Enables version 2 log format (journal format supporting
              larger log buffers).

              This option only applies to the deprecated V4 format.

       -l     Print the current filesystem label.

       -p     Enable 32bit project identifier support (PROJID32BIT
              feature).

              This option only applies to the deprecated V4 format.

       -u     Print the current filesystem UUID (Universally Unique
              IDentifier).

       -c 0|1 Enable (1) or disable (0) lazy-counters in the filesystem.

              Lazy-counters may not be disabled on Version 5 superblock
              filesystems (i.e. those with metadata CRCs enabled).

              In other words, this option only applies to the deprecated
              V4 format.

              This operation may take quite a bit of time on large
              filesystems as the entire filesystem needs to be scanned
              when this option is changed.

              With lazy-counters enabled, the superblock is not modified
              or logged on every change of the free-space and inode
              counters. Instead, enough information is kept in other
              parts of the filesystem to be able to maintain the counter
              values without needing to keep them in the superblock.
              This gives significant improvements in performance on some
              configurations and metadata intensive workloads.

       -L label
              Set the filesystem label to label.  XFS filesystem labels
              can be at most 12 characters long; if label is longer than
              12 characters, xfs_admin will truncate it and print a
              warning message.  The filesystem label can be cleared
              using the special "--" value for label.

       -O feature1=status,feature2=status...
              Add or remove features on an existing V5 filesystem.  The
              features should be specified as a comma-separated list.
              status should be either 0 to disable the feature or 1 to
              enable the feature.  Note, however, that most features
              cannot be disabled.

              NOTE: Administrators must ensure the filesystem is clean
              by running xfs_repair -n to inspect the filesystem before
              performing the upgrade.  If corruption is found, recovery
              procedures (e.g. reformat followed by restoration from
              backup; or running xfs_repair without the -n) must be
              followed to clean the filesystem.

              Supported features are as follows:

              inobtcount
                  Keep a count the number of blocks in each inode btree
                  in the AGI.  This reduces mount time by speeding up
                  metadata space reservation calculations.  The
                  filesystem cannot be downgraded after this feature is
                  enabled.  Once enabled, the filesystem will not be
                  writable by older kernels.  This feature was added to
                  Linux 5.10.

              bigtime
                  Upgrade a filesystem to support larger timestamps up
                  to the year 2486.  The filesystem cannot be downgraded
                  after this feature is enabled.  Once enabled, the
                  filesystem will not be mountable by older kernels.
                  This feature was added to Linux 5.10.

       -U uuid
              Set the UUID of the filesystem to uuid.  A sample UUID
              looks like this: "c1b9d5a2-f162-11cf-9ece-0020afc76f16".
              The uuid may also be nil, which will set the filesystem
              UUID to the null UUID.  The uuid may also be generate,
              which will generate a new UUID for the filesystem.  Note
              that on CRC-enabled filesystems, this will set an
              incompatible flag such that older kernels will not be able
              to mount the filesystem.  To remove this incompatible
              flag, use restore, which will restore the original UUID
              and remove the incompatible feature flag as needed.

       -r rtdev
              Specifies the device special file where the filesystem's
              realtime section resides.  Only for those filesystems
              which use a realtime section.

       -V     Prints the version number and exits.

       The mount(8) manual entry describes how to mount a filesystem
       using its label or UUID, rather than its block special device
       name.

SEE ALSO         top

       mkfs.xfs(8), mount(8), xfs_db(8), xfs_growfs(8), xfs_repair(8),
       xfs(5).

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
       2021-04-01.  (At that time, the date of the most recent commit
       that was found in the repository was 2021-03-12.)  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_admin(8)

Pages that refer to this page: fstab(5)xfs(5)mkfs.xfs(8)mount(8)xfs_db(8)xfs_repair(8)