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

1AboutHPStorageWorks

C o ntinuous Access EVA

HP StorageWorks Continuous Access EVA is the remote replication component of HP StorageWorks

Enterprise Virtual Array (EVA) controller software. When this component is licensed and conﬁgured,

the controller copies data online, in real time, to a remote array over a storage area network (SAN).

Properly conﬁgured, HP Continuous Access EVA is a disaster-tolerant storage solution that ensures data

integrity if an array or site fails. You must have an HP Stora geWorks Continuous Access EVA license to

use this feature.

This chapter describes HP Continuous Access EVA features, concepts, and interfaces.

Features

HP Continuo

us Access EVA features include:

• Continuous replication of local virtual disks on remote virtual disks

• Synchronous and asynchronous remote replication

• Automated

failover

• Failsafe data protection mode

• Ability to suspend and resume replication

• Bidirecti

onal replication

• Graphical and command-line user interfaces

• Automatic suspense of replication if the link between arrays is down

For suppo

rted maximums, see the p roduct release notes.

Remote replication concepts

Remote replication is the continuous copying of data from selected virtual disks on a local (source)

array to related virtual disks on a remote (destination) array. Applications continue to run while data

replicates in the backgr ound over a separate connection. Remote replication r equires a fabric connection

between the local and remote arrays and a logical relationship (DR group) between source virtual disks

and destination virtual disks.

Replication modes

The remote replication modes are asynchronous and synchronous. In asynchronous mo d e, the array

acknow

ledges I/O completion before data is replicated on the remote array. In synchronous mode,

the arr

ay acknowledges I/O completion after the data is cached on the local and remote arrays.

Async

hronous mode provides faster response to the host ser ver and synchronous mode provides greater

data p

rotection. The choice of asyn chronous o r synchronous mode is generally a business decision

and ha

s implications for bandwidth re quirements. For information about the performance impact of

choosing asynchronous or synchronous replication mode, see the HP Continuous Access EVA Performance

Estimator user guide.

You s

et the replication mode when you create data replication (DR) groups.

HP StorageWorks Continuous Access EVA administrator guide