HP StorageWorks XP24000 Continuous Access Journal Software User and Reference Guide, v01 (T5278-96001, June 2007)

Figure 26 3DC Multi-target Conﬁguration (Combining Con tin uous Access Journal with

Continuous Access Synchronous)

In this conﬁguration, the primary volume at the primary site is paired with the secondary volume for

Continuous Access Synchronous. This primary volume is also paired with the secondary volume for

Continuous Access Journal. If a host at the primary site writes data to the primary volume, the data will be

written to the Continuous Access Synchronous secondary volume in real time, synchronously with writing

from thehost. Thedatawillalsobewritten to theContinuousAccessJournal secondarydatavolume,

asynchronously with writing from the host. Update sequence consistency will be maintained with the

Continuous Access Journal secondary d ata volume.

Since writing from the Continuous Access Journal primary volume to the Continuous Access Journal

secondary volume is performed asyn chronously with writing from the host to the primary volume, this

conﬁguration can prevent a delay in the response to the host, even if the Continuous Access Journal

primary site and the Continuous Access Journal secondary site are far from each other.

For detailed information about the hardware conﬁguration required for a 3D C multi-target c on ﬁguration,

see “ Hardware Conﬁguration”onpage62.

If a failure occurs in a Continuous Access Synchronous primary volume which is also used as a Continuous

Access Journal primary data volume, you can resume the business tasks by using the Continuous Access

Synchronous secondary volume. After you resume the business tasks, you need to remove the failure from

the

primary volume and transfer the business tasks back to the primary site.

If a failure occurs in both the primary volume and the Continuous Access Synchronous secondary volume,

you can resume your business tasks by using the Continuous Access Journal secondary data volume. After

you resume the business tasks, you need to remove the failure from the primary volume and the Continuous

Access Synchronous secondary volume, and transfer the business tasks b ack to the primary site.

Hardw

are Conﬁguration

A comp

uter system in a 3D C multi-target conﬁguration requires the following three s ites:

• Primary site for both Continuous Access Synchronous and Continuous Access Journal

• Secondary site for Continuous Access Synchronous

• Seco

ndary site for Continuous Access Journal

Each of these sites requires one storage system and Remote Web Console c omputers. HP recommends

that RAID Manager be installed in the host computers at each of these sites.

The following explains the hardware conﬁguration for storage systems at these sites:

• Storage system at t h e primar y site:

•The

storage system must have Continuous Access Synchronous installed.

• The storagesystem musthaveContinuousAccess Journalinstalled.

Preparing for Continuous Access Journal Operations