1xfs_admin(8) System Manager's Manual xfs_admin(8)
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6 xfs_admin - change parameters of an XFS filesystem
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9 xfs_admin [ -eflpu ] [ -c 0|1 ] [ -L label ] [ -U uuid ] device [
10 logdev ]
11 xfs_admin -V
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14 xfs_admin uses the xfs_db(8) command to modify various parameters of a
15 filesystem.
16 Devices that are mounted cannot be modified, except as noted below.
18 Administrators must unmount filesystems before xfs_admin or xfs_db(8)
19 can convert parameters. A number of parameters of a mounted filesystem
20 can be examined and modified using the xfs_growfs(8) command.
21 The optional logdev parameter specifies the device special file where
23 the filesystem's external log resides. This is required only for
24 filesystems that use an external log. See the mkfs.xfs -l option, and
25 refer to xfs(5) for a detailed description of the XFS log.
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28 -e Enables unwritten extent support on a filesystem that does not
29 already have this enabled (for legacy filesystems, it can't be
30 disabled anymore at mkfs time).
31 -f Specifies that the filesystem image to be processed is stored in
33 a regular file at device (see the mkfs.xfs -d file option).
34 -j Enables version 2 log format (journal format supporting larger
36 log buffers).
37 -l Print the current filesystem label. This command can be run if
39 the filesystem is mounted.
40 -p Enable 32bit project identifier support (PROJID32BIT feature).
42 -u Print the current filesystem UUID (Universally Unique IDenti‐
44 fier).
45 -c 0|1 [22mEnable (1) or disable (0) lazy-counters in the filesystem.
47 Lazy-counters may not be disabled on Version 5 superblock
49 filesystems (i.e. those with metadata CRCs enabled).
50 This operation may take quite a bit of time on large filesystems
52 as the entire filesystem needs to be scanned when this option is
53 changed.
54 With lazy-counters enabled, the superblock is not modified or
56 logged on every change of the free-space and inode counters.
57 Instead, enough information is kept in other parts of the
58 filesystem to be able to maintain the counter values without
59 needing to keep them in the superblock. This gives significant
60 improvements in performance on some configurations and metadata
61 intensive workloads.
62 -L label
64 Set the filesystem label to label. XFS filesystem labels can be
65 at most 12 characters long; if label is longer than 12 charac‐
66 ters, xfs_admin will truncate it and print a warning message.
67 The filesystem label can be cleared using the special "--" value
68 for label. This command can be run if the filesystem is
69 mounted.
70 -U uuid
72 Set the UUID of the filesystem to uuid. A sample UUID looks
73 like this: "c1b9d5a2-f162-11cf-9ece-0020afc76f16". The uuid may
74 also be nil, which will set the filesystem UUID to the null
75 UUID. The uuid may also be generate, which will generate a new
76 UUID for the filesystem. Note that on CRC-enabled filesystems,
77 this will set an incompatible flag such that older kernels will
78 not be able to mount the filesystem. To remove this incompati‐
79 ble flag, use restore, which will restore the original UUID and
80 remove the incompatible feature flag as needed.
81 -V Prints the version number and exits.
83 The mount(8) manual entry describes how to mount a filesystem using its
85 label or UUID, rather than its block special device name.
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88 mkfs.xfs(8), mount(8), xfs_db(8), xfs_growfs(8), xfs_repair(8), xfs(5).
89 xfs_admin(8)