HP 3PAR StoreServ Cluster Extension Software Installation Guide (5697-2895, December 2013)

How HP 3PAR StoreServ Cluster Extension Software interacts with its
environment
This section describes the ways in which HP 3PAR StoreServ Cluster Extension interacts with its
environment.
Failover function
HP 3PAR StoreServ 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 virtual volumes 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 HP 3PAR StoreServ Cluster Extension utilizes virtual volumes
To write to HP 3PAR Remote Copy paired virtual volumes, you must ensure that the paired virtual
volumes are in read/write mode. Volume group members (paired virtual volumes) are in read/write
mode on the source (primary) virtual volume only. The destination (secondary) virtual volume is in
read-only mode.
• In case of a failover, HP 3PAR StoreServ 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 volume group
members. HP 3PAR StoreServ Cluster Extension Software determines whether those virtual
volumes can be accessed and made available to the application service.
How HP 3PAR StoreServ Cluster Extension stores information
HP 3PAR StoreServ Cluster Extension stores information about the application environment in an
internal object database and uses HP 3PAR CLI to gather information about the state of the
associated volume 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.
Virtual volume states are stored in the internal object database, which uses a rule engine to process
those states. The rule engine matches current volume group member states and configuration
parameters with a defined rule, stores it in the database, and invokes predefined actions. Those
actions prepare the volume group member virtual volumes 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 HP 3PAR StoreServ Cluster Extension.
Ensure that the following conditions are met before installing HP 3PAR StoreServ Cluster Extension
Software:
• HP Remote Copy links (including extender hardware) are redundant and bidirectional.
• Alternate I/O paths (network and storage links) between servers and the HP 3PAR StoreServ
Storage 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 HP 3PAR StoreServ Storage and servers are installed.
• The cluster nodes in your zoning configuration each recognize their respective (local) HP 3PAR
StoreServ Storage, but not the remote HP 3PAR StoreServ Storage.
6 Preparing to install HP 3PAR StoreServ Cluster Extension