Managing Serviceguard Extension for SAP Version B.05.10, December 2012

NOTE: Packages that have several Netweaver instances configured, continue to monitor all the
instances that are not manually halted. If any actively monitored instance fails, it results in a failover
and restart of the whole package.
One of the methods to restart a manually halted instance is to issue the following command:
sapcontrol -nr <instancenr> -function Start
Any other startup method provided by SAP's sapcontrol command works in the similar way.
Example of messages added to the package log:
<date> root@<node> sapdisp.mon[xxx]: (sapdisp.mon,check_if_stopped):
Manual start operation detected for DVEBMGS41
<date> root@<node> sapdisp.mon[xxx]: (sapdisp.mon,check_if_stopped):
Resume monitored operation of DVEBMGS41
If the instance fails to start, the service monitor enters the yellow state. The yellow state is printed
as a warning to the package log and displayed as a package alert in the HP Serviceguard
Manager.
<date> root@<node> sapdisp.mon[xxx]: (sapdisp.mon,check_if_stopped):
Resume monitored operation of DVEBMGS41
<date> root@<node> sapdisp.mon[xxx]: (sapdisp.mon,dispmon_monitors):
WARNING: Dispatcher of DVEBMGS41 - monitor state:YELLOW,2
The service monitor remains in yellow state for up to five monitoring intervals. Then, it changes
to red state and fails the package with the next monitoring interval. If another instance halt
operation is issued while the monitor is in yellow or red state, the monitoring is suspended again
and the package failover is prevented. This occurs regardless of whether the manual halt succeeds
or not. It is an effective way to prevent undesirable failovers.
Triggering a package halt is possible whether instances of the package are currently halted or
not. The operation causes the cluster to loose information about all the instances that were manually
halted during the package run. Subsequent package attempts to start the instances in the package.
NOTE: Activating package maintenance mode is a way to pause all SGeSAP service monitors
of a package immediately, but it can only be triggered with Serviceguard commands directly.
While package maintenance mode is active, failover of the package is disabled. Maintenance
mode also works for instances without HA library configured.
Change Management
Serviceguard keeps information about the cluster configuration. It especially needs to know the
relocatable IP addresses and its subnets, your Volume Groups, the Logical Volumes and their
mountpoints. Check with your HP consultant for information about the way Serviceguard is
configured to suite your SAP system. If you change this configuration, you may have to change
and reapply the cluster configuration accordingly.
System Level Changes
SGeSAP provides some flexibility for hardware change management. If you have to maintain the
server on which an (A)SCS instance is running, this instance can temporarily be moved to the host
that runs its Replicated Enqueue without interrupting ongoing work. Some users might experience
a short delay in the response time for their ongoing transaction. No downtime is required for the
maintenance action.
If you add new hardware and SAP software needs access to it to work properly, make sure to
allow this access from any host of the cluster by appropriately planning the hardware connectivity.
For example, it is possible to increase database disk space by adding a new shared LUN from a
SAN device as physical volume to the shared volume groups on the primary host on which a
Change Management 23