Clear checksum error in FreeNAS/TrueNAS

Clear checksum error in FreeNAS/TrueNAS

Identify error

Errors can be found in TrueNAS Storage section in web page, or use shell in web page, run zpool status -x command.

Sample error can be fond in following screen. There are two pools got error. The pool0 got two hard disks, first one got 154 checksum errors, second one got one data error.

  pool: pool0
 state: ONLINE
status: One or more devices has experienced an unrecoverable error.  An
    attempt was made to correct the error.  Applications are unaffected.
action: Determine if the device needs to be replaced, and clear the errors
    using 'zpool clear' or replace the device with 'zpool replace'.
   see: https://openzfs.github.io/openzfs-docs/msg/ZFS-8000-9P
  scan: scrub repaired 0B in 00:00:02 with 0 errors on Sat Oct  2 17:39:46 2021
config:

    NAME                                            STATE     READ WRITE CKSUM
    pool0                                           ONLINE       0     0     0
      mirror-0                                      ONLINE       0     0     0
        gptid/bf410fcf-2209-11ec-b8aa-001132dbfc9c  ONLINE       0     0   154
        gptid/bfcc498a-2209-11ec-b8aa-001132dbfc9c  ONLINE       0     0     0

errors: No known data errors

  pool: pool01
 state: ONLINE
status: One or more devices has experienced an error resulting in data
    corruption.  Applications may be affected.
action: Restore the file in question if possible.  Otherwise restore the
    entire pool from backup.
   see: https://openzfs.github.io/openzfs-docs/msg/ZFS-8000-8A
config:

    NAME                                          STATE     READ WRITE CKSUM
    pool01                                        ONLINE       0     0     0
      gptid/75827da1-207a-11ec-afcf-005056a390b2  ONLINE       0     0     1
errors: List of errors unavailable: permission denied

errors: 1 data errors, use '-v' for a list

For second error, impacted file can be found using zpool status -v command

root@truenas[~]# zpool status -v pool01
  pool: pool01
 state: ONLINE
status: One or more devices has experienced an error resulting in data
        corruption.  Applications may be affected.
action: Restore the file in question if possible.  Otherwise restore the
        entire pool from backup.
   see: https://openzfs.github.io/openzfs-docs/msg/ZFS-8000-8A
  scan: scrub repaired 0B in 00:23:22 with 1 errors on Sat Oct  2 21:53:02 2021
config:

        NAME                                          STATE     READ WRITE CKSUM
        pool01                                        ONLINE       0     0     0
          gptid/75827da1-207a-11ec-afcf-005056a390b2  ONLINE       0     0     1

errors: Permanent errors have been detected in the following files:

        /mnt/pool01/download/file.1
root@truenas[~]#

Clear error

Run following command to clear the error

zpool clear <pool_name>

For the pool has data error, which has any file impacted. Delete or overwrite the file.

Then scrub the pool

zpool scrub <pool_name>

Replace disk

To replace disk, run following command, c0t0d2 is a new disk to replace c0t0d0

zpool replace c0t0d0 c0t0d2

If the disk replaced at same location, then run following command

zpool replace c0t0d0

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