Red Hat CLUSTER SUITE - CONFIGURING AND MANAGING A CLUSTER 2006 Manual page 156

140 Appendix A. Supplementary Hardware Information
Figure A-1. Single-controller RAID Array Connected to Single-initiator Fibre Chan-
nel Interconnects
The external RAID array must have a separate SCSI channel for each cluster node. In
clusters with more than two nodes, connect each node to the SCSI channel on the RAID
array, using a single-initiator SCSI bus as shown in Figure A-1.
To connect multiple cluster nodes to the same host port on the RAID array, use a Fibre
Channel hub or switch. In this case, each host bus adapter is connected to the hub or
switch, and the hub or switch is connected to a host port on the RAID controller.
A Fibre Channel hub or switch is also required with a dual-controller RAID array with two
host ports on each controller. This configuration is shown in Figure A-2. Additional cluster
nodes may be connected to either Fibre Channel hub or switch shown in the diagram. Some
RAID arrays include a built-in hub so that each host port is already connected to each of
the internal RAID controllers. In this case, an additional external hub or switch may not be
needed.