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

Command-line interface (CLI)
P9000 Cluster Extension Software provides a CLI to enable disaster tolerance without cluster
software. The CLI is convenient if you use in-house software to migrate application services from
one system to another or if you want P9000 Cluster Extension to check disk states to make sure
you can automatically start an application service on the local disk array.
Fast Failback using Continuous Access
P9000 Cluster Extension supports the RAID Manager Fast Failback feature. This feature allows the
Continuous Access software to automatically redirect the mirroring direction of a disk pair even if
the remote RAID Manager instance is not available. This ensures the fastest possible recovery to
the original site in case of an application service failover at the alternate site.
P9000 Cluster Extension configurations
P9000 Cluster Extension is an array-based solution. It requires at least two P9000 or XP disk arrays
with the Continuous Access software providing remote mirroring. P9000 Cluster Extension connects
the disk array software with the cluster software, and uses the cluster software to react to system
hardware and application failures.
Servers are members of the same cluster dispersed over two or more sites.
P9000 Cluster Extension supports one-to-one and consolidated-site configurations.
One-to-one configurations
In one-to-one (1:1) configurations, cluster host nodes are split between two geographically separate
data centers and use redundant, diversely routed network connections for intra-cluster
communications. For an example of a one-to-one configuration, see “One-to-one (1:1) configuration”
(page 9). These links must be as reliable as possible to prevent false failover operations or
split-brain situations.
Figure 1 One-to-one (1:1) configuration
Command-line interface (CLI) 9