3.4. Deploying Composite Active/Active Clusters

A Composite Active/Active (CAP) Cluster topology provides all the benefits of a typical dataservice at a single location, but with the benefit of also replicating the information to another site. The underlying configuration within Tungsten Cluster uses two services within each node; one provides the replication within the cluster, and the second provides replication from the remote cluster. Both are managed by the Tungsten Manager

Note

Composite Active/Active Clusters were previously referred to as Multi-Site/Active-Active (MSAA) clusters. The name has been updated to reflect the nature of these clusters as part of an overall active/active deployment using clusters, where the individual clusters could be in the same or different locations.

Whilst the older Multi-Site/Active-Active topology is still valid and supported, it is recommended that this newer Composite Active/Active topology is adopted from version 6 of Tungsten Cluster onwards. For details on the older topology, see Section 3.3, “Deploying Multi-Site/Active-Active Clustering”

The configuration is handled with a single configuration and deployment that configures the core cluster services and additional cross-cluster services.

A sample display of how this operates is provided in Figure 3.4, “Topologies: Composite Active/Active Clusters”.

Figure 3.4. Topologies: Composite Active/Active Clusters

Topologies: Composite Active/Active Clusters

The service can be described as follows:

  • Tungsten Cluster Service: east

    Replicates data between east1, east2 and east3.

  • Tungsten Cluster Service: west

    Replicates data between west1, west2 and west3.

  • Tungsten Cluster Service: west_from_east

    Defines the replication service using a secondary sub-service within the cluster. This service reads THL FROM east and writes to the relay node in west, subsequently, the replica nodes within west are then replicated to from there.

  • Tungsten Replicator Service: east_from_west

    Defines the replication service using a secondary sub-service within the cluster. This service reads THL FROM west and writes to the relay node in east, subsequently, the replica nodes within east are then replicated to from there.