Guidelines for State Database Replicas

• You can add additional state database replicas to the system at any time. The additional state database replicas help ensure Solaris Volume Manager availability.

  ---

  Caution –

  If you upgraded from Solstice DiskSuite^TM to Solaris Volume Manager and you have state database replicas sharing slices with file systems or logical volumes (as opposed to on separate slices), do not delete the existing replicas and replace them with new replicas in the same location.

  The default state database replica size in Solaris Volume Manager is 8192 blocks, while the default size in Solstice DiskSuite was 1034 blocks. If you delete a default-sized state database replica from Solstice DiskSuite, then add a new default-sized replica with Solaris Volume Manager, you will overwrite the first 7158 blocks of any file system that occupies the rest of the shared slice, thus destroying the data.

  ---

• When a state database replica is placed on a slice that becomes part of a volume, the capacity of the volume is reduced by the space that is occupied by the replica(s). The space used by a replica is rounded up to the next cylinder boundary and this space is skipped by the volume.

• By default, the size of a state database replica is 4 Mbytes or 8192 disk blocks. Because your disk slices might not be that small, you might want to resize a slice to hold the state database replica. For information about resizing a slice, see “Administering Disks (Tasks)” in System Administration Guide: Basic Administration.

• If multiple controllers exist, replicas should be distributed as evenly as possible across all controllers. This strategy provides redundancy in case a controller fails and also helps balance the load. If multiple disks exist on a controller, at least two of the disks on each controller should store a replica.