The AliveMsgTolerance value specifies how many exchanged messages from a host can be missed before the cluster initiates ...

The AliveMsgTolerance value specifies how many exchanged messages from a host can be missed before the cluster initiates convergence. You should pick this number based on your failover requirements. Increasing the number of message exchanges prior to convergence will reduce the number of unnecessary convergence initiations due to transient network congestion, but it will also increase the failover delay.