NAME

       xfs_admin - change parameters of an XFS filesystem

SYNOPSIS

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

DESCRIPTION

       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

       -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

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

                                                                                                    xfs_admin(8)