Examples of Remote Copy Architectures

The rest of the chapter looks at a couple of different remote copy designs.

"Ping Pong" Remote Copy Between Two Sites

In this example a company has two data centers in the same region or city. Each of them has primary storage and uses the other for secondary storage in a remote copy system.

Figure 10-7 shows two sites named East and West. Both sites have storage and remote copy controllers providing forwarding and receiving roles. If one site experiences a problem, the work resumes at the other site. Companies with multiple data centers sometimes use this type of arrangement because they have full-time staff available in both locations.

Figure 10-7. Two Sites Providing Secondary Storage for the Other

While it is not often done, this type of arrangement could also be used by two different organizations with compatible systems and storage products. Sharing the cost of remote copy could make the technology affordable for companies that cannot afford to implement it alone.

Bunker Secondary Storage and Remote Tertiary Storage

The bunker approach is shown in Figure 10-8. Writes are sent from a forwarding remote copy controller to secondary storage in a bunker site connected by a high-speed MAN network using synchronous remote copy mode. From there writes are sent to tertiary storage in a distant remote site over a slower WAN network using asynchronous mode.

Figure 10-8. Remote Copy Using Bunker Storage on a High-Speed Network and Tertiary Storage Over a WAN