Compaq ProLiant 1600 Administrator's Manual page 51

2-20 Compaq ProLiant Clusters HA/F100 and HA/F200 Administrator Guide
If the host bus adapter-to-storage hub path fails, it results in a failover of all
applications. For instance, if one server can no longer access the storage hub
(and by extension the shared storage), all of the cluster groups that depend on
shared storage will fail over to the second server. The cost of failure is
relatively minor. It is the downtime experienced by users while the failover
event occurs.
Note that the Compaq Insight Manager tools monitor the health of the RA4000
storage system. If any part of the Fibre Channel data path disrupts a server's
access to the RA4000, the array controller status changes to "Failed" and the
condition is red. The red condition bubbles up to higher-level Compaq Insight
Manager screens and eventually to the device list.
NOTE: The Compaq Insight Manager tools display a failure of physical hardware through
the Mass Storage button on the View screen, marking the hardware "Failed." A logical
drive in the cluster is reported on the Cluster Shared Resources screen as a logical disk
resource. Compaq Insight Manager and Compaq Insight Manager XE do not associate the
logical drive with the physical hardware.
Failure of the Hub-to-RA4000 Data Path
ProLiant
Server
Figure 2-11. Hub-to-RA4000 data path
The second data path, from the storage hub to the RA4000, has more severe
implications when it fails. If this data path fails, all clustered applications
become inoperable. Even attempting to fail the applications to another cluster
node will not gain access to the RA4000.
NOTE: This failure scenario can be avoided by deploying the redundant Fibre Channel
loop configuration of the Compaq ProLiant Cluster HA/F200.
RA4000
storage hub
Interconnect
ProLiant
Server
Corporate LAN