HP 3PAR StoreServ Cluster Extension Software Administrator Guide (5697-2894, December 2013)

1-to-1 configuration
When setting up a one-to-one configuration (see Figure 2 (page 10)), consider the following:
• Cluster nodes are split between two or more geographically dispersed data center sites and
use redundant, diversely routed network connections for intra-cluster communications. Those
links must be as reliable as possible to prevent false failover operations or split-brain situations.
• Each cluster node connected to a HP 3PAR StoreServ Storage should have redundant I/O
paths to the HP 3PAR StoreServ Storage. Connections to both the source (primary) and the
destination (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 StoreServ
Storage.
• 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 StoreServ Storage because you do not need to change the mirroring
direction of the Remote Copy volume group members.
• You can deploy HP 3PAR StoreServ Cluster Extension in environments where several clusters
use the same HP 3PAR StoreServ Storage pair.
• You can use HP 3PAR Remote Copy in synchronous replication mode between two HP 3PAR
StoreServ Storage connected using FC switches and extender hardware.
• HP 3PAR StoreServ 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.
Storage system configurations 9