Bidirectional active/passive replication

For any given pair of HCP systems, each system can serve as both a primary system and a replica for the other system, as long as different HCP tenants and different default-namespace directories are being replicated in each direction. A system that serves as both a primary system and a replica at the same time has two active/passive links: one outbound and one inbound. This topology is called bidirectional active/passive replication.

What this looks like

The following figure shows a bidirectional active/passive replication topology in which two systems (A and B) are each replicating to the other system.

Bidirectional active/passive replication topology

In this figure:

  • From system A, two locally created tenants are being replicated to system B. In both tenants, all namespaces are selected for replication.
  • From system B, one locally created tenant is being replicated to system A. In this tenant, all namespaces are selected for replication.

Uses

For each link in a bidirectional active/passive replication topology, the tenants, namespaces, and directories being replicated are read-write on the primary system and read-only on the replica. Therefore, a bidirectional active/passive replication topology supports a scenario like this:

  • Application 1 running in a data center in New York needs read-write access to Tenant-1, which was created locally in the HCP system (A) in New York.
  • Application 2 running in a data center in Tokyo needs read-write access to Tenant-2, which was created locally in the HCP system (B) in Tokyo.
  • Application 1 needs only read access to Tenant-2.
  • Application 2 needs only read access to Tenant-1

To meet these needs, you could:

  • Create an active/passive link from system A to system B that includes Tenant-1. System A sends Tenant-1 to system B, where the tenant is in read-only mode. Application 2 can access the tenant more efficiently on system B than on system A.
  • Create an active/passive link from system B to system A that includes Tenant-2. System B sends Tenant-2 to system A, where the tenant is in read-only mode. Application 1 can access the tenant more efficiently on system A than on system B.