A
Cabling and Termination Required to Expand a Cluster
This appendix summarizes how to expand a basic (two-server, single RAID subsystem) cluster to support additional servers and/or a second RAID subsystem. This appendix assumes that the pre-installation, hardware and software configuration procedures for a basic cluster have been performed as described in this guide, and focuses only on the procedures required for cluster expansion.
A.1 Hardware Configuration of an Expanded Cluster
A basic cluster, (2 server, single RAID subsystem) configured in an End-Bus RAID or Mid-Bus RAID cluster layout, can be expanded in two ways:
1.By adding host servers to a single SCSI bus
2.By adding a second RAID subsystem via a separate SCSI bus
Figure A-1 shows an expanded cluster, where one or more servers have been added the cluster by extending the SCSI bus of the basic cluster, and a second RAID subsystem has been added on a separate SCSI bus. Both RAID subsystems can be accessed by all clustered servers.
The two heartbeats shown in Figure A-1 represent the failover capabilities configurable between clustered servers using MC/ServiceGuard software. In other words, all servers with MC/ServiceGuard software can be configured to failover any other server in the cluster that has MC/ServiceGuard software.
The cabling and termination required to expand a cluster are discussed and illustrated in the following sections.
