Managing Serviceguard Extension for SAP on Linux (IA64 Integrity and x86_64), February 2008

SAP Supply Chain Management
Serviceguard Extension for SAP on Linux Package Configuration
Chapter 4202
Service Monitoring
SAP recommends the use of service monitoring in order to evaluate the
availability of liveCache processes. The Serviceguard service monitor,
provided with Serviceguard Extension for SAP on Linux, periodically
checks the availability and responsiveness of the liveCache system. The
sanity of the monitor will be ensured by standard Serviceguard
functionality.
The liveCache monitoring program is shipped with Serviceguard
Extension for SAP on Linux as the saplc.mon file. The monitor runs as a
service attached to the lc<LCSID> Serviceguard package.
If the monitor recognizes the liveCache to be unavailable, it will try to
restart liveCache on the node it is currently running. If this does not
succeed, the runtime operating system resources of liveCache are
cleaned up and another local restart attempt is made. If the liveCache
instance still cannot be started, Serviceguard will switch the package
and try to restart on another cluster node.
Monitoring begins with package startup. At this point, the monitor will
make sure, that liveCache is working only up to the point that is
specified in LCSTARTMODE. For example, if LCSTARTMODE=OFFLINE is set
in file sap.config, only the vserver processes will be part of the
monitoring. Still, the monitor detects any manual state change of
liveCache. By subsequent manual operations, liveCache will be entering
cold state and finally warm state, which the monitor automatically
detects. As soon as the liveCache reaches the warm state once, the
monitoring increases its internal monitoring level to the same state.
As with any Serviceguard Extension for SAP on Linux package, the (lc)
package will skip any SAP specific startup steps when during startup a
file called debug is found in either ${SGCONF}/<LCSID>/debug or
${SGCONF}/debug. When the debug file is found only the liveCache
specific volumes will be mounted and a virtual IP address is set. This is
useful for debugging purposes to allow access to the logfiles placed on
shared logical volumes if a package does not start up to its full extent.
The lc monitor is started regardless of the availability of a debug file. The
monitor will detect the existence of the file and will enter a pause mode
until it is removed. This is valid not only during package startup, but
also at runtime. As a consequence, the monitoring of a fully started
package will be paused by the global debug file.