Failure Detector Configuration
A failure detector is responsible to determine if a member in the cluster is unreachable or crashed. The most important problem in failure detection is to distinguish whether a member is still alive but slow or has crashed. But according to the famous FLP result, it is impossible to distinguish a crashed member from a slow one in an asynchronous system. A workaround to this limitation is to use unreliable failure detectors. An unreliable failure detector allows a member to suspect that others have failed, usually based on liveness criteria but it can make mistakes to a certain degree.
Hazelcast has the following built-in failure detectors: Deadline Failure Detector and Phi Accrual Failure Detector.
There is also a Ping Failure Detector, that, if enabled, works in parallel with the above ones, but identifies the failures on OSI Layer 3 (Network Layer). This detector is by default disabled.
Note that, Hazelcast also offers failure detectors for its Java client. See the Client Failure Detectors section for more information.