ZFS Log Device Recovery

Solaris 10 10/09 Release: In this release, ZFS identifies intent log failures in the zpool status command output. Fault Management Architecture (FMA) reports these errors as well. Both ZFS and FMA describe how to recover from an intent log failure.

For example, if the system shuts down abruptly before synchronous write operations are committed to a pool with a separate log device, you see messages similar to the following:

# zpool status -x
  pool: pool
 state: FAULTED
status: One or more of the intent logs could not be read.
        Waiting for adminstrator intervention to fix the faulted pool.
action: Either restore the affected device(s) and run 'zpool online',
        or ignore the intent log records by running 'zpool clear'.
 scrub: none requested
config:

        NAME        STATE     READ WRITE CKSUM
        pool        FAULTED      0     0     0 bad intent log
          mirror    ONLINE       0     0     0
            c0t1d0  ONLINE       0     0     0
            c0t4d0  ONLINE       0     0     0
        logs        FAULTED      0     0     0 bad intent log
          c0t5d0    UNAVAIL      0     0     0 cannot open

You can resolve the log device failure in the following ways:

• Replace or recover the log device. In this example, the log device is c0t5d0.

• Bring the log device back online.

  # zpool online pool c0t5d0

• Reset the failed log device error condition.

  # zpool clear pool

To recover from this error without replacing the failed log device, you can clear the error with the zpool clear command. In this scenario, the pool will operate in a degraded mode and the log records will be written to the main pool until the separate log device is replaced.

Consider using mirrored log devices to avoid the log device failure scenario.