Sun Cluster HA for SAP Fault Probes

The Sun Cluster HA for SAP fault probe monitors the availability of the Central Instance, specifically the message server, the enqueue server, and the dispatcher. The probe monitors only the local node by checking for the existence of the critical SAP processes. It also uses the SAP utility lgtst to verify that the SAP message server is reachable.

Upon detecting a problem, such as when a process dies prematurely or lgtst reports an error, the fault probe will first try to restart SAP on the local node for a configurable number of times (configurable through hadsconfig(1M)). If the number of restarts that the user has configured has been exhausted, then the fault probe initiates a switchover by calling hactl(1M), if this instance has been configured to allow failover (also configurable through hadsconfig(1M)). The Central Instance is shut down before the switchover occurs, and then is restarted on the remote node after the switchover is complete.

Displaying LOG_DB_WARNING Messages for the SAP Probe

The Sun Cluster HA for SAP parameter LOG_DB_WARNING determines whether warning messages should be displayed if the Sun Cluster HA for SAP probe cannot connect to the database. When LOG_DB_WARNING is set to y and the probe cannot connect to the database, a message is logged at the warning level in the local0 facility. By default, the syslogd(1M) daemon does not display these messages to /dev/console or to /var/adm/messages. To see these warnings, you must modify the /etc/syslog.conf file to display messages of local0.warning priority. For example:

...
*.err;kern.notice;auth.notice;local0.warning /dev/console
*.err;kern.debug;daemon.notice;mail.crit;local0.warning /var/adm/messages
...

After modifying the file, you must restart syslogd(1M). See the syslog.conf(1M) and syslogd(1M) man pages for more information.