HP ProLiant Cluster HA/F500 for Enterprise Virtual Array Enhanced DT Supplement Guide

Introduction
The ProLiant server nodes in the cluster are connected or stretched over a distance.
Up to two storage subsystems for FCIP connections and four storage subsystems for
non-FCIP connections can be used at one site. These storage subsystems act as the
source sites for the Continuous Access software and process disk subsystem requests
for all nodes in the cluster. The storage subsystems are connected to the server nodes
by means of redundant Fibre Channel connections that are managed by Secure Path.
Additionally, the source storage subsystems are connected by means of redundant
longwave fiber/FCIP connections to the destination site. As with standard ProLiant
clusters using Microsoft operating systems, MSCS manages failovers at the server
and application levels.
The Continuous Access software functions at the redundant storage controller level
in each of the storage subsystems and performs synchronous mirroring from the
source site to the destination site, creating an exact copy of the cluster-shared disk.
A manual recovery process performed at the destination site allows access to the
mirrored data in the event of a disaster at the source site. The cluster is functional
again within minutes, and application processing can continue.
There are several types of failover scenarios in an HA/F500 for EVA Enhanced DT
cluster. Some are automatic and others require manual intervention. Because the
nodes are part of a standard MSCS cluster, many failures are recognized and
corrected automatically by MSCS, including server, application, and MSCS
resource failures. In addition, failover caused by Fibre Channel switch/storage
controllers/FCIP link failures are corrected automatically.
Failover scenarios that are not corrected automatically and that require manual
intervention include local storage and entire site failures. The failover and monitoring
logic that is required for a fully automated failover of these types of failures must be
very sophisticated to prevent false failover.
Most companies interested in HA/F500 for EVA Enhanced DT cluster configurations
for entire site failures still want the option of performing the site failover manually.
Additional operations can be performed remotely, using remote monitoring and
control features, such as those found in HP Remote Management products
(HP Integrated Remote Console, Remote Insight Board, and Remote Insight
Lights-Out Edition II).
HP ProLiant Cluster HA/F500 for Enterprise Virtual Array Enhanced DT Supplement Guide 1-3
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