Probing Algorithm and Functionality

Sun Cluster HA for SAP liveCache has a fault monitor for each resource type.

• SAP xserver Fault Monitor (SUNW.sap_xserver)

• liveCache Fault Monitor (SUNW.sap_livecache)

SAP xserver Fault Monitor

The SAP xserver parent process is under the control of process monitor pmfadm. If the parent process is stopped or killed, the process monitor contacts the SAP xserver Fault Monitor, and the SAP xserver Fault Monitor decides what action must be taken.

The SAP xserver Fault Monitor performs the following steps in a loop.

1. Sleeps for Thorough_probe_interval.

2. Uses the SAP utility dbmcli with db_enum to check SAP xserver availability.

   • If SAP xserver is unavailable, SAP xserver probe restarts or fails over the SAP xserver resource if it reaches the maximum number of restarts.

   • If any system error messages are logged in syslog during the checking process, the SAP xserver probe concludes that a partial failure has occurred. If the system error messages logged in syslog occur four times within the probe_interval, SAP xserver probe restarts SAP xserver.

liveCache Fault Monitor

The liveCache probe checks for the presence of the liveCache parent process, the state of the liveCache database, and whether the user intentionally stopped liveCache outside of Sun Cluster software. If a user used the Stop liveCache button in LC10 or the lcinit command to stop liveCache outside of Sun Cluster software, the liveCache probe concludes that the user intentionally stopped liveCache outside of Sun Cluster software.

If the user intentionally stopped liveCache outside of Sun Cluster software by using the Stop liveCache button in LC10 or the lcinit command, the Sun Cluster HA for SAP liveCache Fault Monitor updates the resource state and status message to reflect this action, but it does not restart liveCache. When the user successfully restarts liveCache outside of Sun Cluster software by using the Start liveCache button in LC10 or the lcinit command, the Sun Cluster HA for SAP liveCache Fault Monitor updates the resource state and status message to indicate that liveCache is running under the control of Sun Cluster software, and Sun Cluster HA for SAP liveCache Fault Monitor takes appropriate action if it detects liveCache is OFFLINE.

If liveCache database state reports that liveCache is not running or that the liveCache parent process terminated, the Sun Cluster HA for SAP liveCache Fault Monitor restarts or fails over liveCache.

The Sun Cluster HA for SAP liveCache Fault Monitor performs the following steps in a loop. If any step returns liveCache is offline, the liveCache probe restarts or fails over liveCache.

1. Sleeps for Thorough_probe_interval.

2. Uses the dbmcli utility with db_state to check the liveCache database state.

3. If liveCache is online, liveCache probe checks the liveCache parent process.

   • If the parent process terminates, liveCache probe returns liveCache is offline.

   • If the parent process is online, liveCache probe returns OK.

4. If liveCache is not online, liveCache probe determines if the user stopped liveCache outside of Sun Cluster software by using the Stop liveCache button in LC10 or the lcinit command.

5. If the user stopped liveCache outside of Sun Cluster software by using the Stop liveCache button in LC10 or the lcinit command, returns OK.

6. If the user did not stop liveCache outside of Sun Cluster software by using the Stop liveCache button in LC10 or the lcinit command, checks SAP xserver availability.

   • If SAP xserver is unavailable, returns OK because the probe cannot restart liveCache if SAP xserver is unavailable.

   • If SAP xserver is available, returns liveCache is offline.

7. If any errors are reported from system function calls, returns system failure.