Bidirectional active-passive replication with disaster recovery support

You can combine the bidirectional and one-to-many replication topologies to create a configuration in which each of two systems replicates its locally created HCP tenants and namespaces and default-namespace directories to both the other system and a third system. This third system then provides each of the first two systems with both additional assurance of continuous data availability and disaster recovery functionality.

For example, suppose HCP systems A and B each replicate their locally created HCP tenants and namespaces and default-namespace directories to each other, and you want a third system, C, to provide disaster recovery functionality for each of those systems. To create this combined topology:

Create a link from A to B that includes all the HCP tenants and namespaces and default-namespace directories that were originally created on system A.

Create a link from A to C that includes the same tenants, namespaces, and directories as the link from A to B.

Create a link from B to A that includes all the HCP tenants and namespaces and default-namespace directories that were originally created on system B.

Create a link from B to C that includes the same tenants, namespaces, and directories as the link from B to A.

The figure below shows a bidirectional replication topology with disaster recovery support.

You can combine the bidirectional and chained replication topologies to have the same result as the topology described above, which involves the bidirectional and one-to-many topologies. That is, the replicated items in the link from A to B also end up on C, and the replicated items in the link from B to A also end up on C.

In this case, however, instead of the link from A to C replicating the same items as the link from A to B, the link from A to C would include the link from B to A. Likewise, instead of the link from B to C replicating the same items as the link from B to A, the link from B to C would include the link from A to B.

The figure below shows this topology.

This topology provides better performance than does the first topology described above. Additionally, if you need to add a tenant to the link from A to B, for example, you don’t need to also add it to the link from A to C. Instead, the tenant is automatically replicated to C because the link from A to B is included in the link from B to C.

On the other hand, the first topology described above is better for assuring continuous data availability in the case of the failure of system A or B. For example, if system A is replicating to systems B and C and system B fails, the items being replicated from system A are still making it to system C. In the second topology, if system B fails, the items from system A are not replicated to system C because the replication chain is broken.

Trademarks and Legal Disclaimer

© 2017 Hitachi Data Systems Corporation. All rights reserved.