.TH xfs_admin 8
.SH NAME
xfs_admin \- change parameters of an XFS filesystem
.SH SYNOPSIS
.nf
\f3xfs_admin\f1 [ \f3-elu\f1] [ \f3\-L \f2label\f1 ] [ \f3\-U \f2uuid\f1 ] device
\f3xfs_admin \-f\f1 [ \f3-elu\f1] [ \f3\-L \f2label\f1 ] [ \f3\-U \f2uuid\f1 ] filename
.fi
.SH DESCRIPTION
.I xfs_admin
uses the
.IR xfs_db (8)
command to modify various parameters of a filesystem.
.PP
Devices that are mounted cannot be modified.
Administrators must unmount filesystems before
.I xfs_admin
or
.I xfs_db
can convert parameters.
A number of parameters of a mounted filesystem can be examined
and modified using the
.IR xfs_growfs (8)
command.
.SH OPTIONS
.TP 5
\f3\-e\f1
Enables unwritten extent support on a filesystem that does not
already have this enabled.
.TP 5
\f3\-f\f1
Specifies that the filesystem image to be processed is stored in a
regular file (see the \f2mkfs.xfs\f1 \f3\-d\f1 \f2file\f1 option).
.TP 5
\f3\-j\f1
Enables version 2 log format (journal format supporting larger
log buffers).
.TP 5
\f3\-l\f1
Print the current filesystem label.
.TP 5
\f3\-u\f1
Print the current filesystem UUID (Universally Unique IDentifier).
.TP 5
\f3\-L\f1 \f2label\f1
Set the filesystem label.
XFS filesystem labels can be at most 12 characters long; if
.I label
is longer than 12 characters,
.I xfs_admin
will truncate it and print a warning message.
The filesystem label can be cleared using the special ``\c
.BR \-\- ''
value for
.IR label .
.TP 5
\f3\-U\f1 \f2UUID\f1
Set the UUID of the filesystem.
A sample UUID looks like this: "c1b9d5a2-f162-11cf-9ece-0020afc76f16".
The uuid may also be
.IR nil ,
which will set the filesystem UUID to the null UUID.
The uuid may also be
.IR generate ,
which will generate a new UUID for the filesystem.
.PP
The
.IR mount (8)
manual entry describes how to mount a filesystem using its label or UUID,
rather than its block special device name.
.SH SEE ALSO
mkfs.xfs(8),
mount(8),
xfs_db(8),
xfs_growfs(8),
xfs(5).