Example Three-Room Configuration

A three-room configuration is defined as follows:

• Three separate rooms

• Two rooms with one node each and an equal number of disk arrays, in this case, Sun StorEdge A5x00 disk subsystems; data is mirrored across disk-subsystems in these rooms

• Third room with at least one disk subsystem attached to both hosts to be used as a quorum device

Figure A-2 shows this configuration using Sun StorEdge A5x00 disk arrays. Note that, unlike Figure A-1, which used Sun StorEdge T3 disk trays, this configuration does not use Fibre Channel switches to connect Sun StorEdge A5x00 disk arrays. (Switches are not needed, as long-wave GBICs are already present in the A5x00s and should also be present in the servers' host bus adapters.)

Figure A-2 Example Three-Room Configuration

In this configuration, as long as at least two rooms are up and communicating, recovery will be automatic. This is the only configuration in which loss of any one room is guaranteed to be automatically handled. Loss of two rooms requires the replacement or rebuilding of one room and typically requires SunService intervention.