HP StorageWorks P9000 Cluster Extension Software Administrator Guide (TB534-96009, February 2011)

asynchronous replication modes, see the Continuous Access documentation. For information about
journal replication, see the Continuous Access Journal documentation.
The Continuous Access fence level is used to configure the remote replication feature of a P9000
or XP disk array based on your requirements for application service availability, data concurrency,
and replication performance. P9000 Cluster Extension supports all Continuous Access fence levels:
NEVER, DATA, and JOURNAL.
P9000 Cluster Extension is supported with the Continuous Access Software in the configurations
described in the HP StorageWorks SAN Design Reference Guide, available at http://www.hp.com/
go/sdgmanuals.
P9000 Cluster Extension server configurations
The ideal cluster configuration for P9000 Cluster Extension consists of at least four servers (two at
each site) and separate redundant communications links for cluster heartbeats, client access, and
the Continuous Access Software. Installing communications interfaces in pairs allows failover and
prevents single points of failure (SPOFs). Using four servers provides faster recovery from a system
failure by allowing local application services to fail over to a local cluster system instead of the
remote system. On the remote site, HP recommends that two systems be available in case one
system experiences a hardware or power failure. In addition to at least four servers, the MNS
configuration requires an additional node per cluster, located at a third site so that whenever a
disaster affects either the local or remote site, the other site together with the added node would
have a majority. In a MNS with File Share Witness configuration, the, file share should be located
at the third site.
TIP: To upgrade the array microcode while the application service is running, use host load
balancing and multipathing software, such as Auto Path, HP MPIO Full Featured Device Specific
Module (DSM).
P9000 Cluster Extension allows you to configure the failover behavior so that the application
service startup is stopped if no remote cluster members can be reached. The default configuration
of P9000 Cluster Extension expects the cluster software to deal with the split-brain syndrome.
Planning for P9000 Cluster Extension
Before configuring P9000 Cluster Extension resources
Before configuring P9000 Cluster Extension resources for the Windows CLI implementation or Unix
environments, review the P9000 Cluster Extension objects in the UCF.cfg file. For more information
about P9000 Cluster Extension objects, see “User configuration file and P9000 Cluster Extension
objects” (page 79).
Cluster setup considerations
For cluster setup considerations that apply to Windows and Linux, see:
• “MNS quorum clusters (MSCS)” (page 11)
• “SLE HA cluster setup considerations” (page 12)
• “RHCS cluster setup considerations” (page 14)
MNS quorum clusters (MSCS)
In an MNS cluster, the cluster service is allowed to start or run only if it has access to the majority
of the configured nodes.
Planning for P9000 Cluster Extension 11