1xfs_admin(8) System Manager's Manual xfs_admin(8)
2
6 xfs_admin - change parameters of an XFS filesystem
7
9 xfs_admin [ -eflpu ] [ -O featurelist ] [ -c 0|1 ] [ -L label ] [ -U
10 uuid ] [ -r rtdev ] device [ logdev ]
11 xfs_admin -V
12
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 un‐
18 mount filesystems before xfs_admin or xfs_db(8) can convert parameters.
19 A number of parameters of a mounted filesystem can be examined and mod‐
20 ified 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.
26
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 This option only applies to the deprecated V4 format.
33 -f Specifies that the filesystem image to be processed is stored in
35 a regular file at device (see the mkfs.xfs -d file option).
36 -j Enables version 2 log format (journal format supporting larger
38 log buffers).
39 This option only applies to the deprecated V4 format.
41 -l Print the current filesystem label.
43 -p Enable 32bit project identifier support (PROJID32BIT feature).
45 This option only applies to the deprecated V4 format.
47 -u Print the current filesystem UUID (Universally Unique IDenti‐
49 fier).
50 -c 0|1 [22mEnable (1) or disable (0) lazy-counters in the filesystem.
52 Lazy-counters may not be disabled on Version 5 superblock
54 filesystems (i.e. those with metadata CRCs enabled).
55 In other words, this option only applies to the deprecated V4
57 format.
58 This operation may take quite a bit of time on large filesystems
60 as the entire filesystem needs to be scanned when this option is
61 changed.
62 With lazy-counters enabled, the superblock is not modified or
64 logged on every change of the free-space and inode counters. In‐
65 stead, enough information is kept in other parts of the filesys‐
66 tem to be able to maintain the counter values without needing to
67 keep them in the superblock. This gives significant improvements
68 in performance on some configurations and metadata intensive
69 workloads.
70 -L label
72 Set the filesystem label to label. XFS filesystem labels can be
73 at most 12 characters long; if label is longer than 12 charac‐
74 ters, xfs_admin will truncate it and print a warning message.
75 The filesystem label can be cleared using the special "--" value
76 for label.
77 -O feature1=status,feature2=status...
79 Add or remove features on an existing V5 filesystem. The fea‐
80 tures should be specified as a comma-separated list. status
81 should be either 0 to disable the feature or 1 to enable the
82 feature. Note, however, that most features cannot be disabled.
83 NOTE: Administrators must ensure the filesystem is clean by run‐
85 ning xfs_repair -n to inspect the filesystem before performing
86 the upgrade. If corruption is found, recovery procedures (e.g.
87 reformat followed by restoration from backup; or running xfs_re‐
88 pair without the -n) must be followed to clean the filesystem.
89 Supported features are as follows:
91 inobtcount
93 Keep a count the number of blocks in each inode btree in the
94 AGI. This reduces mount time by speeding up metadata space
95 reservation calculations. The filesystem cannot be down‐
96 graded after this feature is enabled. Once enabled, the
97 filesystem will not be writable by older kernels. This fea‐
98 ture was added to Linux 5.10.
99 bigtime
101 Upgrade a filesystem to support larger timestamps up to the
102 year 2486. The filesystem cannot be downgraded after this
103 feature is enabled. Once enabled, the filesystem will not
104 be mountable by older kernels. This feature was added to
105 Linux 5.10.
106 nrext64
108 Upgrade a filesystem to support large per-inode extent coun‐
109 ters. The maximum data fork extent count will be 2^48 - 1,
110 while the maximum attribute fork extent count will be 2^32 -
111 1. The filesystem cannot be downgraded after this feature is
112 enabled. Once enabled, the filesystem will not be mountable
113 by older kernels. This feature was added to Linux 5.19.
114 -U uuid
116 Set the UUID of the filesystem to uuid. A sample UUID looks
117 like this: "c1b9d5a2-f162-11cf-9ece-0020afc76f16". The uuid may
118 also be nil, which will set the filesystem UUID to the null
119 UUID. The uuid may also be generate, which will generate a new
120 UUID for the filesystem. Note that on CRC-enabled filesystems,
121 this will set an incompatible flag such that older kernels will
122 not be able to mount the filesystem. To remove this incompati‐
123 ble flag, use restore, which will restore the original UUID and
124 remove the incompatible feature flag as needed.
125 -r rtdev
127 Specifies the device special file where the filesystem's real‐
128 time section resides. Only for those filesystems which use a
129 realtime section.
130 -V Prints the version number and exits.
132 The mount(8) manual entry describes how to mount a filesystem using its
134 label or UUID, rather than its block special device name.
135
137 mkfs.xfs(8), mount(8), xfs_db(8), xfs_growfs(8), xfs_repair(8), xfs(5).
138 xfs_admin(8)