Since potentially significant differences exist in your communications environment, you have the capability to adjust variables that affect cluster communications to best match your environment.
The default values should normally be acceptable to most common environments. If your particular environment is not well suited for these defaults, you can tune cluster communications to better match your environment. Two levels of tuning are available.
Base-level tuning allows you to set the tuning parameters to a predefined set of values identified for high, low, and normal timeout and messaging interval values. When the normal level is selected, the default values are used for cluster communications performance and configuration parameters. Selecting the low level causes clustering to increase the heartbeating interval and the various message timeout values. With fewer heartbeats and longer timeout values, the cluster will be less sensitive to communications failures. Selecting the high level causes clustering to decrease the heartbeating interval and the various message timeout values. With more frequent heartbeats and shorter timeout values, the cluster will be more sensitive to communications failures.
Advanced-level tuning is also available such that individual parameters may be tuned over predefined ranges of values. This allows more granular tuning to meet any special circumstances in your communications environment. If an advanced level of tuning is desired, it is recommended that you obtain help from IBM® support personnel or equivalent. Setting the individual parameters incorrectly can easily result in decreased performance.