Peer or Master and Secondary Relationships

Members of a fault-tolerant group can be configured as peers or as master and secondary engines. If all engines are peers, when the machine containing the currently active process engine fails, another peer process engine resumes processing for the first engine, and continues processing until its machine fails.

If the engines are configured as master and secondary, the secondary engine resumes processing when the master fails. The secondary engine continues processing until the master recovers. Once the master recovers, the secondary engine stands by and the master takes over processing again.

The Fault Tolerance tab of the Process Engine deployment resource allows you to specify the member weight of each member of a fault-tolerant group. The member with the highest weight is the master. You can select "Peer" in the first field on the tab to configure all engines as peers (that is, they all have the same weight). You can select Primary or Secondary to configure the engines as master and secondary. You can also select Custom to specify your own values for the weight of each member of the group.