HP P6000 Cluster Extension Software Installation Guide (5697-2275, November 2012)

Failover function
P6000 Cluster Extension Software requires cluster software to automatically fail over among systems
on a local site or between sites. Because the software manipulates the application startup process
before storage system vdisks are accessed, it must be integrated as the first resource (in the order
of resources). The software must be installed on all servers in the cluster that can run the application
service.
How P6000 Cluster Extension utilizes vdisks
To write to P6000 Continuous Access paired vdisks, you must make sure the paired vdisks are in
read/write mode. DR group members (paired vdisks) are usually in read/write mode on the source
(primary) vdisk only. The destination (secondary) vdisk is in read-only mode.
• In case of a failover, P6000 Cluster Extension Software automatically changes the direction
of the mirrored pair. A reboot of the server is not necessary.
• In case of a disaster, the storage system can have several different states for DR group members.
P6000 Cluster Extension Software determines whether those vdisks can be accessed and
made available to the application service.
How P6000 Cluster Extension stores information
P6000 Cluster Extension stores information about the application environment in an internal object
database and uses HP P6000/EVA SMI-S to gather information about the state of the associated
DR group members. Information about the configured storage system environment and failover
behavior is transferred either directly by the cluster software or by gathering it from the user
configuration file. An internal object database provides the software with the format and default
value of supported parameters.
Vdisk states are stored in the internal object database, which uses a rule engine to process those
DR group member states. The rule engine matches current DR group member states and configuration
parameters with a defined rule, stores it in the database, and invokes predefined actions. Those
actions prepare the DR group member vdisks to be enabled for access or stop the application
service startup process if the matching rule requires a stop.
General installation prerequisites
This section describes general installation prerequisites for P6000 Cluster Extension.
Environmental setup
Ensure that the following conditions are met before installing P6000 Cluster Extension Software:
• P6000 Continuous Access links (including extender hardware) are redundant and bidirectional.
• Alternate I/O paths between servers and the P6000/EVA storage system are set up.
• Cluster and client networks are redundant.
• Cluster nodes can communicate with each other.
• The latest supported software and firmware versions, fixes, FC adapter firmware, and driver
versions for your servers and P6000/EVA storage systems are installed.
• The cluster nodes in your zoning configuration each recognize their respective (local)
P6000/EVA array, but not the remote P6000/EVA array. Each management server recognizes
both P6000/EVA arrays and can recognize each other.Figure 1 (page 7) shows a zoning
example.
6 Preparing to install P6000 Cluster Extension