Failover of active update sources

You can use failover of active update sources to ensure that when a server that is the active update source for a section of the topic tree becomes unavailable, an update source on another server is assigned to be the active update source for that section of the topic tree. Failover of active update sources is enabled for any sections of the topic tree that have topic replication enabled.

A client must register as an update source to update a replicated topic. Replicated topics cannot be updated non-exclusively. For more information about update sources, see Updating topics.

A client (CLIENT 1) connects to a Diffusion™ server (SERVER 1) and registers an update source for a section of the topic tree that has topic replication enabled. This update source is the active update source.
Another client (CLIENT 2) connects to another Diffusion server (SERVER 2) and registers an update source for the same section of the topic tree. This update source is a standby update source.
The topics on SERVER 2 continue to receive their updates from CLIENT 1 through the datagrid.
If SERVER 1 or CLIENT 1becomes unavailable, the update source registered by CLIENT 2 becomes active. SERVER 2 sends CLIENT 2 a callback to notify it that it is the active update source.

On SERVER 2, the topics in that section of the topic tree receive their updates from CLIENT 2. SERVER 2 reflects this topic data into the datagrid.

Considerations

Consider the following factors when using failover of active update sources:

If the topic paths that the updating client uses to register an update source do not match the topic paths configured in the Replication.xml configuration file of the server, unexpected behavior can occur.
The mechanism that provides failover of active update sources assumes that all servers have the same configuration and that all control clients implement the same behavior as part of a scalable and highly available deployment. If this is not the case, unexpected behavior can occur.