Longest Service Interruption

In most situations, the longest service interruption is no longer than the activation interval.

Cascading Failure Situations

Cascading failure is an unusual situation in which several members fail in succession—either as they activate, or toward the end of their activation interval. As a result, several activation intervals may elapse before service is restored (or the supply of inactive members is exhausted).

Cascading failure can result from fatal program errors during activation, or from a rare coincidence of unrelated failures.

New Member Situations

When a new member joins a group, Rendezvous fault tolerance software identifies the new member to existing members (if any), and then waits for a period of one activation interval to receive identification from them in return. If, at the end of this interval, it determines that too few members are active, then it instructs the new member to activate.