Managing HP Serviceguard Extension for SAP for Linux, December 2013

The described functionality can be achieved by adding the module sgesap/sapextinstance
to the package.
NOTE: Declaring non-critical Dialog Instances in a package configuration does not add them to
the components that are secured by the package. The package won't react to any error conditions
of these additional instances. The concept is distinct from the Dialog Instance packages that got
explained in the previous section.
If Additional Dialog Instances are used, then follow the below rules:
• Use saplogon with Application Server logon groups. When logging on to an application
server group with two or more Dialog Instances, you don't need a different login procedure
even if one of the Application Servers of the group fails. Also, using login groups provides
workload balancing between Application Servers.
• Avoid specifying a destination host when defining a batch job. This allows the batch scheduler
to choose a batch server that is available at the start time of the batch job. If you must specify
a destination host, specify the batch server running on the Central Instance or a packaged
Application Server Instance.
• Print requests stay in the system until a node is available again and the Spool Server has been
restarted. These requests could be moved manually to other spool servers if one spool server
is unavailable for a long period of time. An alternative is to print all time-critical documents
through the highly available spool server of the central instance.
• Configuring the Update Service as part of the packaged Central Instance is recommended.
Consider using local update servers only if performance issues require it. In this case, configure
Update Services for application services running on the same node. This ensures that the
remaining SAP Instances on different nodes are not affected if an outage occurs on the Update
Server. Otherwise, a failure of the Update Service will lead to subsequent outages at different
Dialog Instance nodes.
22 SAP cluster concepts