xfs_admin uses the xfs_db(8) command to modify various parameters of
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.
-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
-l Print the current filesystem label.
-p Enable 32bit project identifier support (PROJID32BIT feature).
-u Print the current filesystem UUID (Universally Unique
-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.
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.
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
-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.
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, see
⟨http://oss.sgi.com/bugzilla/buglist.cgi?product=XFS⟩. This page was
obtained from the project's upstream Git repository
⟨git://oss.sgi.com/xfs/cmds/xfsprogs⟩ on 2017-03-13. 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