HP P9000 Business Continuity Manager User Guide

Figure 11 2DC Configuration Example
A 2DC configuration offers the following advantages:
• If a disaster occurs at the primary site, the S-VOL of the Continuous Access Asynchronous for
Mainframe or Continuous Access Journal for Mainframe copy pair at the secondary site can
be used to restart and continue operations, without waiting for primary site recovery.
• When a disaster occurs at the primary site, even if the S-VOL for the Continuous Access
Asynchronous for Mainframe or Continuous Access Journal for Mainframe copy pair on the
secondary site cannot be used for a recovery, the operation data is not completely lost because
there is also a backup on the Business Copy for Mainframe copy pair S-VOL.
• Operation data can be backed up to a Business Copy for Mainframe copy pair S-VOL,
minimizing the time necessary to recover the backup data.
The 3DC configurations
A 3DC configuration minimizes the chances of losing data in the event of a disaster by allocating
copies to three different sites.
A 3DC configuration performs a remote copy with a local site nearby (where Continuous Access
Synchronous for Mainframe operations are performed) and a remote site (where Continuous Access
Journal for Mainframe operations are performed). Copy pairs between each site can be set to
maintain DUPLEX status.
A 3DC configuration offers the following advantages:
• The copy pairs between each site can always be left in the DUPLEX status, to set the retention
time for the update order consistency to 0.
• The copying operation is simple.
Copy pairs between sites can be set to maintain DUPLEX status. Once a copy pair has been
changed to DUPLEX status, it is not necessary to specify operation on that copy pair unless
the status is suspended by an error or the site is damaged by a disaster.
There are three types of 3DC configurations:
• 3DC Cascade configuration
• 3DC Multi-Target configuration
• Delta Resync configuration
Replication products and data center configurations 43