6.2. Red Hat Cluster Suite Timers

When Oracle RAC is installed, Red Hat Cluster Suite must interact with Oracle Clusterware, but also is in control of the timeouts and eventually the fencing. When Oracle HA is configured, Red Hat Cluster Suite is also in charge, so the timeouts are very similar.

All installations will have subtly different timeout requirements, but start with these recommended settings:

<cluster config_version="11" name="dl585">
  <fence_daemon clean_start="1" post_fail_delay="0"post_join_delay="3" />
  <quorumd device="/dev/mapper/qdisk" interval="2" log_level="5" tko="8" votes="1" />
  <cman expected_votes="3" two_node="0" />
  <totem token="33000" />

In this example, the quorum disk is the level fencing mechanism with a timeout of 16 seconds; that is, two intervals of 8 seconds. The tko parameter stands for Technical Knock Out — a boxing metaphor. The CMAN heartbeat timeouts must be more than two time the tko timeouts; we choose 33 seconds (value in ms). This delay gives the quorum daemon adequate time to establish which node is the master during a failure, or if there is a load spike that might delay voting. The expected_votes parameter is set to the number of nodes + 1.