Using Serviceguard Extension for RAC, 4th Edition, February 2007

Maintenance and Troubleshooting
Replacing Disks
Chapter 4208
On-line Hardware Maintenance with In-line SCSI
Terminator
Serviceguard allows on-line SCSI disk controller hardware repairs to all
cluster nodes if you use HP’s in-line terminator (C2980A) on nodes
connected to the end of the shared FW/SCSI bus. The in-line terminator
cable is a 0.5 meter extension cable with the terminator on the male end,
which connects to the controller card for an external bus. The in-line
terminator is used instead of the termination pack that is attached to the
controller card and makes it possible to physically disconnect the node
from the end of the F/W SCSI bus without breaking the bus's
termination. (Nodes attached to the middle of a bus using a Y cable also
can be detached from the bus without harm.) When using in-line
terminators and Y cables, ensure that all orange-socketed termination
packs are removed from the controller cards.
NOTE You cannot use inline terminators with internal FW/SCSI buses on D
and K series systems, and you cannot use the inline terminator with
single-ended SCSI buses. You must not use an inline terminator to
connect a node to a Y cable.
Figure 4-1 shows a three-node cluster with two F/W SCSI buses. The
solid line and the dotted line represent different buses, both of which
have inline terminators attached to nodes 1 and 3. Y cables are also
shown attached to node 2.