L2ARC is Disabled in the Solaris 10 10/08 Release (6730309)

The output of the zpool upgrade -v command identifies L2ARC cache devices as available. However, cache devices are not available in the Solaris 10 10/08 release. Various error messages are displayed:

• If you attempt to add a cache device to a ZFS storage pool when it is created, you will see the following message:

  # zpool create pool mirror c1t1d0 c1t2d0 cache c1t3d0 cannot create 'pool': operation not supported on this type of pool

• If you attempt to add a cache device to an existing pool, you will see the following message:

  # zpool add pool cache c1t3d0 cannot add to 'pool': pool must be upgraded to add these vdevs

Workaround: None.