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)