HP StorageWorks Continuous Access EVA Administrator Guide (T3687-96043, December 2005)

NOTE:

Failover can take other forms in the EVA environment:

• Controller failover is the process that takes place when one controller in a pair assumes the workload

ofafailedorredirectedcompanioncontrollerinthesamecabinet.

• Fabric or path failover is the act of transferring I/O operations from one fabric or path to another.

This guide describes the failover of DR groups and managed sets. It does not address controller failover

within a cabinet, or path or fabric failov er because redundancy is assumed.

Here are some facts about failover:

• Failover is permitted only on a destination DR group.

• If only one comp onent fails, repairing the component can be preferable to failing over the

whole site.

Figure 2 shows data replication among DR groups at three locations. Arrays 1 and 4 are at the local site,

andarrays2and5areataremotesite.Onthelocalsite,array1containssourceDRgroups(replicating

to array 2), and array 4 contains destination DR groups (replicated from array 5). If the arrays at the

local site become unavailable, the destination DR groups on array 2 fail over and become source D R

groups (in failover state), providing storage for the hosts that were using array 1. On array 5, the source

DR groups begin lo g ging until the local site is re-established or replaced with another destination.

HP StorageWorks Continuous Access EVA administrator guide