NAME

       xfs_admin - change parameters of an XFS filesystem

SYNOPSIS

       xfs_admin [ -eflpu ] [ -c 0|1 ] [ -L label ] [ -U uuid ] device
       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.

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).

       -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).

       -l     Print the current filesystem label.

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

       -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).

              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.

       -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.

       -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)