Chapter 9. Freeing space on thinly-provisioned logical volumes using fstrim
Chapter 9. Freeing space on thinly-provisioned logical volumes using fstrim You can manually run fstrim to return unused logical volume space to the thin pool, which can be available for other logical volumes. Red Hat recommends running fstrim daily. Prerequisites Verify that the thin pool logical volume supports discard behavior. Discard is supported if the output of the following command for the underlying device is not zero. Note If discard_max_bytes returns 0, you can still execute the fstrim command on the thin logical volume to reclaim unused blocks to the thin pool. However, the discard or trim will not be passed down to the block layer. Procedure Run fstrim to restore physical space to the thin pool. For example, the following command discards any unused space it finds on the logical volume mounted at /gluster_bricks/data/data , and provides verbose output ( -v ).
cat /sys/block/<device>/queue/discard_max_bytes fstrim -v <mountpoint> fstrim -v /gluster_bricks/data/data