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

Disaster Recovery
Resource Failover
A cluster failover occurs if a cluster resource fails at one of the sites (refer to
Figure 3-1). The exact failover behavior can be configured for each cluster group, but
usually this means that the entire cluster group that contains the failed resource may
attempt to switch to the other cluster node. No storage subsystem failover is required
in this scenario.
You are given the opportunity to select a preferred path during the creation of the
Vdisks. This means that host I/O to a Vdisk will go to the controller you designate as
preferred, as long as the paths to that controller are available. The two failover-only
options available to Microsoft Windows platforms (failover-A and failover-B when
you set up Vdisks) allow the host to control when a Vdisk moves to a preferred path.
For example, if path A is preferred and that path becomes unavailable, path B is used.
The host will then control the movement back to path A when it becomes available
later.
Figure 3-1: Fabric or controller failure
3-2 HP ProLiant Cluster HA/F500 for Enterprise Virtual Array Enhanced DT Supplement Guide
HP CONFIDENTIAL
Writer: Woody Jernigan File Name: d-ch3 Disaster Recovery.doc
Codename: 49er IV Part Number: 339223-002 Last Saved On: 9/30/03 10:48 AM