Managing Serviceguard Extension for SAP, December 2007

Understanding Serviceguard Extension for SAP
Combining SGeSAP with Complementary Solutions
Chapter 144
During the initial run, all the generic resources like the shared volume
groups and the file systems of an application, which may influence the
proper operation of that application in the cluster, are specified in the
cluster resource DB. Then, individual configurations for a certain
application or in a certain customer environment can be added whenever
necessary by simply adding the resource definition to the resource DB.
This flexibility enables the Monitor to work with all kinds of
applications. Even in uniform applications like SAP WAS, many
customers have different individual setups and need flexibility to
address this.
The Cluster Consistency Monitor must be run periodically in order to
maintain the cluster failover capability. The current implementation of
the monitor supports a "Learning Mode" which gives detailed
Information about a discovered failure as well as some hints how to fix
the problem. The knowledge of configuring and maintaining a cluster
has been put in the Monitor. On the other side, in case a cluster is well
tuned, this feature may be switched off and the monitor checks only on
changes. Of course, potential problems may be fed into a management
system like HP ITO.
In a small installation consisting only on a few clusters, the output
should be delivered in an ASCII report. It might be however useful to
have a central maintenance server in a large IT infrastructure. The
current implementation of the monitor supports an ASCII report for
standalone operations as well as HTML reports for centralized
infrastructure repositories.
The implemented features of the Cluster Consistency Monitor are as
follows:
• The information to examine is configurable in order to support all
kind of applications.
• Due to the flexibility in configuring resources, any kind of cluster
may be monitored. This includes the basic Serviceguard Cluster,
Metrocluster, and installations of shadow DB as well.
• Updates on the configurations are easy.
• The compare run may be performed automatically as a background
task or individually from the command line.
• The Cluster Consistency Monitor may be used to trigger an event for
a management system like ITO upon an error.