ZFS Data Corruption Errors

The zpool status command also shows whether any known errors are associated with the pool. These errors might have been found during data scrubbing or during normal operation. ZFS maintains a persistent log of all data errors associated with a pool. This log is rotated whenever a complete scrub of the system finishes.

Data corruption errors are always fatal. Their presence indicates that at least one application experienced an I/O error due to corrupt data within the pool. Device errors within a redundant pool do not result in data corruption and are not recorded as part of this log. By default, only the number of errors found is displayed. A complete list of errors and their specifics can be found by using the zpool status -v command. For example:

$ zpool status -v system1
pool: system1
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: http://support.oracle.com/msg/ZFS-8000-8A
scan: scrub repaired 0 in 0h0m with 2 errors on Fri Jun 29 16:58:58 2012
config:

NAME           STATE     READ WRITE CKSUM
system1        ONLINE       2     0     0
   c8t0d0      ONLINE       0     0     0
   c8t1d0      ONLINE       2     0     0

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

/system1/file.1

A similar message is also displayed by fmd on the system console and the /var/adm/messages file. These messages can also be tracked by using the fmdump command.

For more information about interpreting data corruption errors, see Identifying the Type of Data Corruption.