19.2. Performing batch block discard

Prerequisites

• The file system is mounted.
• The block device underlying the file system supports physical discard operations.

Procedure

• Use the fstrim utility:

  • To perform discard only on a selected file system, use:

    # fstrim mount-point

  • To perform discard on all mounted file systems, use:

    # fstrim --all

• If you run the fstrim command on:

  • a device that does not support discard operations, or

  • a logical device (LVM or MD) composed of multiple devices, where any one of the device does not support discard operations, the following message displays:

    # fstrim /mnt/non_discard
    
    fstrim: /mnt/non_discard: the discard operation is not supported