ZFS Degraded Pool in Solaris

Solaris 10 and zfs has can provide a considerable amount of control over disk management. On occasion when a disk fails in zfs it will be marked as “REMOVED”, “FAULTED”, “UNAVAILABLE”, or some other unfavorable status. Once this happens to a disk the pool will likely be marked as a “DEGRADED” status. In order to remedy this one will need to rectify the failed disk. It is also a good idea to follow up with a “zpool scrub”.

root@computer:/pool/share# zpool status

  pool: pool
 state: DEGRADED
status: One or more devices could not be used because the label is missing or
        invalid.  Sufficient replicas exist for the pool to continue
        functioning in a degraded state.
action: Replace the device using 'zpool replace'.
   see: http://www.sun.com/msg/ZFS-8000-4J
 scan: resilvered 110K in 0h0m with 0 errors on Thu Jul 28 17:51:09 2011
config:

        NAME               STATE     READ WRITE CKSUM
        pool               DEGRADED     0     0     0
          raidz3-0         DEGRADED     0     0     0
            /disk/disk1    ONLINE       0     0     0
            /disk/disk2    ONLINE       0     0     0
            /disk/disk3    ONLINE       0     0     0
            spare-3        DEGRADED     0     0     0
              /disk/disk4  UNAVAIL      4     1     0  corrupted data
              /disk/disk6  ONLINE       0     0     0
            /disk/disk5    ONLINE       0     0     0
        spares
          /disk/disk6      INUSE     currently in use

errors: No known data errors

In the situation above a disk had an issue, and the hotspare took over. Since there was a hotspare assigned to the pool.

Now we can remove the bad disk using:

root@computer:/pool/share# zpool offline pool /disk/disk4
root@computer:/pool/share# zpool detach pool /disk/disk4
root@computer:/pool/share# zpool status
  pool: pool
 state: ONLINE
 scan: scrub repaired 0 in 0h0m with 0 errors on Thu Jul 28 18:10:11 2011
config:

        NAME             STATE     READ WRITE CKSUM
        pool             ONLINE       0     0     0
          raidz3-0       ONLINE       0     0     0
            /disk/disk1  ONLINE       0     0     0
            /disk/disk2  ONLINE       0     0     0
            /disk/disk3  ONLINE       0     0     0
            /disk/disk6  ONLINE       0     0     0
            /disk/disk5  ONLINE       0     0     0

errors: No known data errors

  pool: rpool
 state: ONLINE
 scan: none requested
config:

        NAME        STATE     READ WRITE CKSUM
        rpool       ONLINE       0     0     0
          c2d0s0    ONLINE       0     0     0

errors: No known data errors

Now disk4 can be replaced with a new or disk. Add the new disk as a hotspare to the pool for better resilience.

root@computer:/pool/share# zpool add pool spare /disk/disk4