Managing Serviceguard Extension for SAP, December 2007

Understanding Serviceguard Extension for SAP
Clustering Stand-Alone J2EE Components
Chapter 1 25
Dedicated NFS Packages
Small clusters with only a few SGeSAP packages usually provide HA
NFS by combining the HA NFS toolkit package functionality with the
SGeSAP packages that contain a database component. The HA NFS
toolkit is a separate product with a set of configuration and control files
that must be customized for the SGeSAP environment. It needs to be
obtained separately.
HA NFS is delivered in a distributed fashion with each database package
serving its own filesystems. By consolidating this into one package, all
NFS serving capabilities can be removed from the database packages.In
complex, consolidated environments with several SGeSAP packages it is
of significant help to use one dedicates HA NFS package instead of
blending this into existing packages.
A dedicated SAPNFS package is specialized to provide access to shared
filesystems that are needed by more than one mySAP component.
Typical filesystems served by SAPNFS would be the common SAP
transport directory or the global SAPDB executable directory. The SAPDB
client libraries are part of the global SAPDB executable directory and
access to these files is needed by APO and liveCache at the same time.
SGeSAP setups are designed to avoid HA NFS shared filesystems with
heavy traffic if possible. For many implementations, this gives the option
to use one SAPNFS package for all HA NFS needs in the SAP
consolidation cluster without the risk to create a serious performance
bottleneck.
HA NFS might still be required in configurations that use Cluster File
Systems in order to provide access to the SAP transport directories to
SAP instances that run on hosts outside of the cluster.