Tuning the Heartbeat Properties

Default heartbeats are created as part of partnership creation. If you use a custom heartbeat, the custom heartbeat should be created before you create a partnership. You can modify the properties of the default and custom heartbeats by using the geohb set-prop command. For more information about this command, refer to the geohb(1M) man page.

Custom heartbeats are provided for special circumstances and require careful configuration. Consult your Sun specialist for assistance if your system requires the use of custom heartbeats.

If you modify the default value of the Query_interval property, ensure that the interval is sufficiently long. An interval that is too short causes a timeout and heartbeat-loss event before the logical hostname resource is available. This failover should result in no more than two unanswered heartbeat requests. Setting a default query_interval value of 120 seconds with the default heartbeat.retries parameter of 3 enables the peer cluster to be unresponsive for 6 minutes (120 * 3 ) without having a false failure declared.

The heartbeat.retries parameter is specified in the com.sun.cluster.agent.geocontol.xml file.

If you adjust the delay setting of the Query_interval property, the following should be true:

Query_interval > worst-case logical-host failover time / 2

You must empirically determine the logical-host failover time for the cluster in question.

The following must be true to avoid false failures:

Query_interval > worst-case logical-host failover time / 3

You should not need to change the heartbeat.retries value. If you want to change the default value of the heartbeat.retries property, contact a Sun specialist.

How to Modify the Heartbeat Properties

Steps

1. Log in to one of the cluster nodes.

   You must be assigned the Geo Management RBAC rights profile to complete this procedure. For more information about RBAC, see Sun Cluster Geographic Edition Software and RBAC.

2. Modify the heartbeat properties.

   # geohb set-prop -p property-setting \ [-p...] heartbeat-name

   -p property-setting

   Sets the default properties of the heartbeat

   A heartbeat property is assigned a value by a name=statement pair. Multiple properties can be set at one time by using multiple statements.

   For more information about the properties you can set, see Appendix A, Standard Sun Cluster Geographic Edition Properties.

   heartbeat-name

   Specifies an identifier for the heartbeat settings

   For information about the names and values that are supported by Sun Cluster Geographic Edition software, see Appendix B, Legal Names and Values of Sun Cluster Geographic Edition Entities.

   For more information about the geohb command, refer to the geohb(1M) man page.

Example 12–7 Modifying the Properties of the Default Heartbeat

The following example illustrates how to modify the settings for the default heartbeat between cluster-paris and cluster-newyork:

# geohb set-prop -p Query_interval=60 hb_cluster-paris~cluster-newyork