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