HP StorageWorks IP Storage Router - Manual (Page 79)

Software Overview
79 IP Storage Router SR2122-2 User Guide
Cluster Management Overview
You can configure storage routers in a cluster to allow the storage routers to back
each other up in case of failure.
Note: A storage router can participate in a cluster only if it is deployed for SCSI
routing.
A storage router cluster consists of two SR2122-2 storage routers connected as
follows:
■ Connected to the same hosts
■ Connected to the same storage systems
■ Connected to each other through their management and high availability (HA)
interfaces
In a cluster, storage routers continually exchange HA information to propagate
configuration data to each other and to detect failures in the cluster. The storage
routers exchange HA information through two separate networks: one connected
to the management interface of each storage router and the other connected to the
HA interface of each storage router. To make sure that HA information is
exchanged reliably between storage routers, the storage routers balance the
transmission of HA information between the management and the HA interfaces.
A storage router cluster supports up to 12 active instances of SCSI routing. At any
given time, an instance of SCSI routing can run on only one storage router in a
cluster. The instance continues running on the storage router where it was started
until one of the following actions occurs:
■ The instance is explicitly stopped or failed over to the other storage router in
the cluster.
■ The instance automatically fails over to another storage router because an
interface is unavailable or another software or hardware problem occurs.
See Chapter 11, “Configuring a High Availability Cluster” for more information
about configuring a high availability cluster.