HP 3PAR Cluster Extension Software Administrator Guide (5697-0925, May 2011)

(secondary) copy of the application disk set are not allowed from the same host. Configure
your servers only in the zone that allows access to the local HP 3PAR storage system.
• HP recommends a minimum of two cluster nodes per site. This allows for preferred local failover
in case of server system failure. Local failover operations are faster than remote failover
between HP 3PAR storage systems because you do not need to change the mirroring direction
of the Remote Copy volume group members.
• You can deploy HP 3PAR Cluster Extension in environments where several clusters use the
same HP 3PAR storage system pair.
• You can use HP 3PAR Remote Copy in synchronous replication mode between two HP 3PAR
storage systems connected using FC switches and extender hardware.
• HP 3PAR Cluster Extension supports synchronous replication mode in all the configurations
supported by HP 3PAR Remote Copy software.
• The HP 3PAR Remote Copy links must have redundant, separately routed links. The cluster
network must have redundant, separately routed links. However, cluster networks and HP
3PAR Remote Copy can share the same links if the link technology is protocol independent
(for example, WDM) or if the FC protocol is transformed into IP.
Figure 2 1-to-1 configuration
N-to-1 and 1-to-N configurations
NOTE: The restrictions outlined in “1-to-1 configuration” (page 8) also apply to N-to-1
configurations.
When setting up an N-to-1 or 1–to-N configuration (see Figure 3 (page 10)), consider the following:
• HP 3PAR Cluster Extension uses the unit of Remote Copy volume groups as the failover unit.
This means all virtual volumes or members of a Remote Copy volume group will be failed over
if the cluster software moves disk access from one cluster node to another.
• A given Windows 3PAR Cluster Extension resource can manage only one Remote Copy volume
group.
Storage system configurations 9