HP EVA Cluster Extension Software Administrator Guide (5697-2445, July 2013)
MSCS
MSCS depends on a quorum resource to maintain a persistent log of cluster configuration changes
and status, as well as a single point to resolve any possible events that could result in a split-brain
situation. EVA Cluster Extension supports the following quorum configurations in which one site
failure will not cause the entire cluster to fail.
Windows Server 2008/2008 R2/2012
• Node Majority
• Node and File Share Majority
Storage system configurations
Cluster configurations typically consist of two or more server systems connected to a shared storage
system. EVA Cluster Extension allows the dispersion of data center resources by enabling cluster
systems to take advantage of EVA storage systems configured for EVA Continuous Access operations.
EVA Cluster Extension connects the EVA management software used to control EVA storage systems
(and EVA Continuous Access) with the cluster software and uses the cluster software to react to
system hardware and application failures.
EVA Cluster Extension behavior is based on four major considerations:
• Cluster software failover behaviors
• EVA Cluster Extension user settings
• The replication mode setting for EVA Continuous Access, which is used to configure the remote
replication feature of an EVA storage system environment based on your needs for application
service availability, data concurrency, and replication performance
• DR group member status information
EVA Cluster Extension supports one-to-one and consolidated DR site configurations.
One-to-one configuration
When setting up a one-to-one configuration (see Figure 2 (page 9)), consider the following:
• Cluster host 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 host node connected to an EVA storage system should have redundant I/O paths
to the EVA storage system. 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 EVA storage system.
• HP recommends a minimum of two cluster host nodes per site. This allows for preferred local
failover in case of system failure. Local failover operations are faster than remote failover
between EVA storage systems because you do not need to change the mirroring direction of
the DR group members.
• You can deploy EVA Cluster Extension in environments where several clusters use the same
EVA storage system pair.
• You can use EVA Continuous Access in synchronous replication mode with EVA Continuous
Access between two EVA storage systems connected using FC switches and extender hardware.
• You can use EVA Continuous Access in enhanced asynchronous mode with Cluster Extension
4.00.01 and later.
8 HP EVA Cluster Extension features