Managing Serviceguard Extension for SAP, December 2007

Planning the Storage Layout
Database Instance Storage Considerations
Chapter 2 69
Oracle Real Application Clusters
Oracle Real Application Clusters (RAC) is an option to the Single
Instance Oracle Database Enterprise Edition. Oracle RAC is a cluster
database with shared cache architecture. The SAP certified solution is
based on HP Serviceguard Cluster File System for RAC.
Handling of a RAC database is not included in SGeSAP itself. The
SGeSAP db and jdb package types can not be used for that purpose. RAC
databases are treated by SGeRAC and Oracle tools, which integrate with
SGeSAP. Standard SGeSAP configurations for SAP instances can be
made using package types ci, jci, d, arep and rep. The configuration of
these is identical to non-RAC environments.
NOTE The configurations are designed to be compliant to SAP OSS note
830982. The note describes SAP recommendations for Oracle RAC
configurations. A support statement from SAP regarding RAC clusters
on HP-UX can be found as part of SAP OSS note 527843. A current
support statement in note 527843 is required, before any of the described
RAC options can be implemented. The note maintenance is done by SAP
and the note content may change at any time without further notice.
Described options may have "Controlled Availability" status at SAP.
Real Application Clusters requires concurrent shared access to Oracle
files from all cluster nodes. This can be achieved by installing the Oracle
software on Cluster File Systems provided by HP Serviceguard Cluster
File System for RAC.
There are node specific files and directories, such as the TNS
configuration. These files and directories are copied to a private file
system on each node. The node specific files and directories are then
removed from the shared disks and symbolic links of the same name are
created, the targets of which are the corresponding files in the private
file system.