Figure 74 3DC CAJ/CAJ solution and mirror unit descriptor usage example

Benefits of 3DC DR Solution

The 3DC DR Solution provides the following benefits:

•Maintains data currency

◦When using 3DC Sync/CAJ solution, synchronous replication over a short distance in a Metrocluster environment provides the highest level of data currency and application availability without significant impact to application performance.

•Maintains high performance

◦When using 3DC CAJ/CAJ solution, asynchronous replication over a long distance in a Metrocluster environment provides the highest level of data consistency and application availability without impacting the application performance.

•The 3DC CAJ/CAJ solution can be used even if there is a high network latency and low network bandwidth between the sites in a Metrocluster. This overcomes the limitations that the 3DC Sync/CAJ solution may have with physical replication links having insufficient bandwidth to cope with application I/O spikes or that might be susceptible to short periods of communication outages.

•Allows swift recovery

◦Metrocluster implementation allows for fast automated failover after a local area disaster.

•Provides a wide area disaster recovery. In case of disaster at one data center, disaster tolerance is achieved with the remaining two data centers.

•In a Tri-Link configuration, there is no single point of failure for data replication following a site outage whereas in Bi-Link configuration it is possible to have this under certain scenarios.

•In Bi-Link configuration, there is no need to have replication links among all the 3 sites. This configuration can be used in scenarios where the replication links does not exist among all the three sites.

•Allows recovery even when a disaster exceeds regional boundaries or extended duration. A wide-area disaster could disable both data centers in Metrocluster, but with semi-automatic

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