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. Administrators must
18 unmount filesystems before xfs_admin or xfs_db(8) can convert parame‐
19 ters. A number of parameters of a mounted filesystem can be examined
20 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.
39 -p Enable 32bit project identifier support (PROJID32BIT feature).
41 -u Print the current filesystem UUID (Universally Unique IDenti‐
43 fier).
44 -c 0|1 [22mEnable (1) or disable (0) lazy-counters in the filesystem.
46 Lazy-counters may not be disabled on Version 5 superblock
48 filesystems (i.e. those with metadata CRCs enabled).
49 This operation may take quite a bit of time on large filesystems
51 as the entire filesystem needs to be scanned when this option is
52 changed.
53 With lazy-counters enabled, the superblock is not modified or
55 logged on every change of the free-space and inode counters.
56 Instead, enough information is kept in other parts of the
57 filesystem to be able to maintain the counter values without
58 needing to keep them in the superblock. This gives significant
59 improvements in performance on some configurations and metadata
60 intensive workloads.
61 -L label
63 Set the filesystem label to label. XFS filesystem labels can be
64 at most 12 characters long; if label is longer than 12 charac‐
65 ters, xfs_admin will truncate it and print a warning message.
66 The filesystem label can be cleared using the special "--" value
67 for label.
68 -U uuid
70 Set the UUID of the filesystem to uuid. A sample UUID looks
71 like this: "c1b9d5a2-f162-11cf-9ece-0020afc76f16". The uuid may
72 also be nil, which will set the filesystem UUID to the null
73 UUID. The uuid may also be generate, which will generate a new
74 UUID for the filesystem. Note that on CRC-enabled filesystems,
75 this will set an incompatible flag such that older kernels will
76 not be able to mount the filesystem. To remove this incompati‐
77 ble flag, use restore, which will restore the original UUID and
78 remove the incompatible feature flag as needed.
79 -V Prints the version number and exits.
81 The mount(8) manual entry describes how to mount a filesystem using its
83 label or UUID, rather than its block special device name.
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86 mkfs.xfs(8), mount(8), xfs_db(8), xfs_growfs(8), xfs_repair(8), xfs(5).
87 xfs_admin(8)