Network Partition Strategies
In case of network failure or an unreachable node, the TCP Transport for TIBCO Hawk might create a network partition and marks the node down based on predefined partition strategies. In network partitioning, the transport keeps the best partition alive and shuts down the other partition. The TCP Transport for TIBCO Hawk handle the network partitions based on the following strategies:
• | Quorum based strategy |
• | Majority based strategy |
Note |
Despite of any strategy, do not add a new Cluster Manager to an already running cluster. |
Quorum-Based Strategy
In the Quorum-based strategy of network partitioning, the network partition has to maintain a minimum number of TCP daemons in the TCP Transport Cluster to be operational. This minimum number of daemons is termed as quorum size. In case of network failure, the cluster with the required quorum size remains operational. The TCP Transport Cluster shuts down the other partition and marks any unreachable node in the other partition as down. For example, there are five Cluster Manager in the cluster with quorum size set to three. If the network partition occurs with one partition having three Cluster Managers and other having two then the partition with two Cluster Managers shuts down.
quorum size = (number of daemons / 2) + 1
Majority-Based Strategy
In the majority based strategy, if the network partition occurs then the partition which has the majority of nodes survives and the other partition shuts down. For example, if there are five nodes in the TCP Transport Cluster and network partition occurs with three and two nodes, then the partition having two nodes shuts itself down. The advantage of the majority based strategy over the Quorum-based strategy is that cluster can gradually downsize without outage. In case, network splits with equal partitions than one which has the oldest node survives.