James's Ramblings

XFS Admin

Created: January 20, 2020
  • xfs_admin can set the filesystem label, display the filesystem UUID, set the filesystem UUID and enable/disable Lazy Counters.

xfs_admin -l DISK

  • Display an XFS filesystem’s label.

xfs_admin -L LABEL DISK

  • Set the label of an XFS fileystem.
  • xfs filesystem labels have an upper length limit of 12 characters.

xfs_admin -U OPTION DISK

  • xfs_admin -U nil DISK # remove a disk's UUID
  • xfs_admin -U restore DISK # reset a disk's UUID to default
  • xfs_admin -U generate DISK # generate a new UUID for the disk

xfs_admin -u DISK

  • Display the UUID on the disk.

xfs_admin -c DISK

  • A superblock is block of data that contains information on how many free inodes exist and how much free space exists on a disk. By default, the superblock is updated every time an operation occurs. If a lot of IO is occuring, it might be necessary to turn the superblock updates off to improve performance.

  • Turning Lazy Counters on turns the regular superblock updates off.

  • Even when Lazy Counters is on, it is possible to get the information about free space/inodes; it’s just slower.