1xfs_admin(8)                System Manager's Manual               xfs_admin(8)
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NAME

6       xfs_admin - change parameters of an XFS filesystem
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SYNOPSIS

9       xfs_admin [ -eflpu ] [ -c 0|1 ] [ -L label ] [ -U uuid ] device
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DESCRIPTION

12       xfs_admin  uses the xfs_db(8) command to modify various parameters of a
13       filesystem.
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15       Devices that are  mounted  cannot  be  modified.   Administrators  must
16       unmount  filesystems  before xfs_admin or xfs_db(8) can convert parame‐
17       ters.  A number of parameters of a mounted filesystem can  be  examined
18       and modified using the xfs_growfs(8) command.
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OPTIONS

21       -e     Enables  unwritten  extent support on a filesystem that does not
22              already have this enabled (for legacy filesystems, it  can't  be
23              disabled anymore at mkfs time).
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25       -f     Specifies that the filesystem image to be processed is stored in
26              a regular file at device (see the mkfs.xfs -d file option).
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28       -j     Enables version 2 log format (journal format  supporting  larger
29              log buffers).
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31       -l     Print the current filesystem label.
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33       -p     Enable 32bit project identifier support (PROJID32BIT feature).
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35       -u     Print  the  current  filesystem UUID (Universally Unique IDenti‐
36              fier).
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38       -c 0|1 Enable (1) or disable (0) lazy-counters in the filesystem.  This
39              operation  may  take quite a bit of time on large filesystems as
40              the entire filesystem needs to be scanned when  this  option  is
41              changed.
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43              With  lazy-counters  enabled,  the superblock is not modified or
44              logged on every change of the  free-space  and  inode  counters.
45              Instead,  enough  information  is  kept  in  other  parts of the
46              filesystem to be able to maintain  the  counter  values  without
47              needing  to  keep them in the superblock. This gives significant
48              improvements in performance on some configurations and  metadata
49              intensive workloads.
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51       -L label
52              Set the filesystem label to label.  XFS filesystem labels can be
53              at most 12 characters long; if label is longer than  12  charac‐
54              ters,  xfs_admin  will  truncate it and print a warning message.
55              The filesystem label can be cleared using the special "--" value
56              for label.
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58       -U uuid
59              Set  the  UUID  of  the filesystem to uuid.  A sample UUID looks
60              like this: "c1b9d5a2-f162-11cf-9ece-0020afc76f16".  The uuid may
61              also  be  nil,  which  will  set the filesystem UUID to the null
62              UUID.  The uuid may also be generate, which will generate a  new
63              UUID for the filesystem.
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65       The mount(8) manual entry describes how to mount a filesystem using its
66       label or UUID, rather than its block special device name.
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SEE ALSO

69       mkfs.xfs(8), mount(8), xfs_db(8), xfs_growfs(8), xfs_repair(8), xfs(5).
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