Managing Serviceguard Extension for SAP, December 2007

Planning the Storage Layout
SAP Instance Storage Considerations
Chapter 258
Option 2: SGeSAP NFS Idle Standby Cluster
This option has a simple setup, but it is severely limited in flexibility. In
most cases, option 1 should be preferred. A cluster can be configured
using option 2 if it fulfills all of the following prerequisites:
• Only one SGeSAP package is configured in the cluster.
• Underlying database technology is a single-instance Oracle RDBMS.
• The package combines failover services for the database and all
required NFS services and SAP central components (ABAP CI, SCS,
ASCS).
• There are no Application Server Instances installed on cluster nodes.
• Replicated Enqueue is not in use.
• There is no additional SAP software installed on the cluster nodes
The use of a HA NFS service can be configured to export file systems to
external Application Servers that manually mount them. A dedicated
NFS package is not possible. Dedicated NFS requires option 1.
Common Directories that are Kept Local
The following common directories and their files are kept local on each
node of the cluster:
• /etc/cmcluster — the directory in which Serviceguard keeps its
configuration files and the node specific package runtime directories.
• /home/<SID>adm — the home directory of the SAP system
administrator with node specific startup log files.
• /usr/sap/<SID>/SYS/exe/run — the directory that holds a local
copy of all SAP instance executables, libraries and tools.
• /usr/sap/tmp — the directory in which the SAP operating system
collector keeps monitoring data of the local operating system.
• Local database client software needs to be stored locally on each
node. Details can be found in the database sections below.
Part of the content of the local group of directories must be synchronized
manually between all nodes of the cluster.