Identifying the Type of Data Corruption

By default, the zpool status command shows only that corruption has occurred, but not where this corruption occurred. For example:

# zpool status
   pool: monkey
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://www.sun.com/msg/ZFS-8000-8A
scrub: none requested
config:

         NAME        STATE     READ WRITE CKSUM
         monkey      ONLINE       0     0     0
           c1t1d0s6  ONLINE       0     0     0
           c1t1d0s7  ONLINE       0     0     0

errors: 8 data errors, use '-v' for a list 

Each error would indicate only that an error occurred at a given point in time. Each error is not necessarily still present on the system. Under normal circumstances, this situation is true. Certain temporary outages might result in data corruption that is automatically repaired once the outage ends. A complete scrub of the pool is guaranteed to examine every active block in the pool, so the error log is reset whenever a scrub finishes. If you determine that the errors are no longer present, and you don't want to wait for a scrub to complete, reset all errors in the pool by using the zpool online command.

If the data corruption is in pool-wide metadata, the output is slightly different. For example:

# zpool status -v morpheus
  pool: morpheus
    id: 1422736890544688191
 state: FAULTED
status: The pool metadata is corrupted.
action: The pool cannot be imported due to damaged devices or data.
   see: http://www.sun.com/msg/ZFS-8000-72
config:

        morpheus    FAULTED   corrupted data
          c1t10d0   ONLINE

In the case of pool-wide corruption, the pool is placed into the FAULTED state, because the pool cannot possibly provide the needed redundancy level.