Host blocking based on task failures
To minimize the possibility of a host being blocked because of a temporary network or disk I/O error, configure heuristic host blocking so that only those hosts on which more tasks fail are blocked.
Heuristic host blocking can be enabled for IBM® Spectrum Symphony and MapReduce workload, with the following differences:
- For IBM Spectrum Symphony workload: The SSM monitors the task failure number on each host in the cluster and blocks a host if its task failure number exceeds a threshold.
- For MapReduce workload: The application manager (SSM) monitors the task failure rate for each host in the cluster and blocks a host if its task failure rate exceeds a threshold. The task failure rate is determined by the total number of task failures on a host in relation to the total number of task failures on other hosts that are being used by the application.