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Multi-datacenter replication

The multi-datacenter capability replicates client sessions and your topic tree in a different data center as part of your Diffusion™ Cloud service.

Note: Multi-datacenter support is only enabled on the Pilot, Launch, Scale, and Dream editions of Diffusion Cloud. For more information, see https://www.diffusiondata.com/pricing/.

If your Diffusion Cloud service fails, the replicated data is used to recover your service from another datacenter within seconds.

The replicated information includes the following items:
  • Security and system authentication configuration
  • All of the client sessions, see Session replication
  • The topic tree (except the Diffusion branch which is used to provide server statistics). For more information, see Topic replication
The replicated information does not include the following items:
  • Any routing topics included in the subset of the topic tree. For more information, see Topic replication
  • All topics in the Diffusion branch. For more information, see Topic replication
  • Console configuration (if this add-on is enabled).

All of your usage and billing information is unaffected by the failure and recovery of your Diffusion Cloud service.

Session replication

If your Diffusion Cloud service becomes unavailable, your clients experience a brief disconnection. When the clients attempt to reconnect on the same URL, they are routed to the recovered service. If the clients are configured to reconnect within 60 seconds, they reconnect to the same session, which has been replicated.

The following session information is replicated:
  • session ID
  • session principal
  • session properties
  • list of topic selections

Topic replication

The replicated data includes a copy of all topics in the topic tree which support replication, excluding the Diffusion branch which contains server statistics. Replicating these topics generates no additional messages.

The following topic types can be replicated:
  • JSON
  • Binary
  • Single value
  • Record
  • Stateless
  • Slave
The following topic information is replicated:
  • The structure of the topic tree excluding the Diffusion branch. Any topics that make up the structure of this branch but are not one of the supported types listed are not created, and the topic definition and data are not replicated. Instead, the topic path of these unsupported topics remains an empty tree node.
  • The topic definitions for all topics outside Diffusion branch. For example, the topic type and any metadata associated with the topic.
  • The topic data for all topics outside the Diffusion branch.

When a client that subscribes to a topic reconnects to the recovered service, it continues to receive updates from the topic.

Replicated topics must be updated by exclusive updates.

When a client that is the active update source for a topic reconnects to the recovered service, it must re-register as a topic update source to continue to update that topic.