Managing HP Serviceguard Extension for SAP for Linux, December 2013

are used in order to allow each node of the cluster to switch roles between serving and using NFS
shares. It is possible to access the NFS file systems from servers outside of the cluster that is an
intrinsic part of many SAP configurations.
4.1.1.1 Common directories that are kept local
The following common directories and their files are kept local on each node of the cluster:
Table 4 List of common directories
DescriptionDirectory
Home directory of the SAP system administrator with node
specific startup log files
/home/<sid>adm
Home directory of the SAP diagnostic agent administrator/home/<dasid>adm
Directory holding local copies of SAP instance executables,
libraries, and tools (optional for kernel 7.x and higher).
/usr/sap/<sid>/SYS/exe/run>
Directory where the SAP operating system collector keeps
monitoring data of the local operating system
/usr/sap/tmp
Directory where SAP control services for the local host are kept
(kernel 7.x and higher).
/usr/sap/hostctrl
CCMS agent work directory (6.40 and 7.00 only)/usr/sap/ccms
List of startup service started by sapinit (boot)/usr/sap/sapservices
Depending on database vendor and version, it might be required to keep local database client
software. Details can be found in the database sections below.
All files belonging to the cluster software and runtime environment are kept local.
Part of the content of the local group of directories must be synchronized manually between all the
nodes of the cluster. Serviceguard provides a tool cmcp(1) that allows replication of a file to all
the cluster nodes.
SAP instance (startup) profile names contain either local hostnames or virtual hostnames. SGeSAP
A.06.00 prefers profiles with virtual hostname and uses those with local hostnames only for fallback
and backwards compatibility.
In clustered SAP environments prior to 7.x releases, executables must be installed locally. Local
executables help to prevent several causes of package startup or package shutdown hangs due
to the unavailability of the centralized executable directory. Availability of executables delivered
with packaged SAP components is mandatory for proper package operation. It is a good practice
to create local copies for all files in the central executable directory. This includes shared libraries
delivered by SAP.
To automatically synchronize local copies of the executables, SAP components deliver the sapcpe
mechanism. With every startup of the instance, sapcpe matches new executables stored centrally
with those stored locally.
4.1.1.2 Directories that Reside on Shared Disks
Volume groups on SAN shared storage are configured as part of the SGeSAP packages. The
volume groups can be following:
• Instance specific
• System specific
• Environment specific
Instance-specific volume groups are required by only one SAP instance or one database instance.
They usually get included with exactly the package that is set up for this instance.
38 SAP Netweaver cluster storage layout planning