HP Serviceguard Extension for SAP (SGeSAP) manual Option 2 SGeSAP NFS Idle Standby Cluster

Table 2-3 System and Environment Specific Volume Groups

Mount Point	Access Point	Potential owning packages VG Name	Device minor
			number
/export/sapmnt/<SID>	shared disk	db<SID>
	and HA NFS	dbci<SID>
		jdb<SID>
		jdbjci<SID>
		sapnfs
/export/usr/sap/trans		db<SID>
		dbci<SID>
		sapnfs
/usr/sap/put	shared disk	none

The tables can be used to document used device minor numbers. The device minor numbers of logical volumes need to be identical for each distributed volume group across all cluster nodes.

/usr/sap/<SID> should not be added to a package, since using this as a dynamic mount point would prohibit access to the instance directories of locally installed additional SAP application servers. The /usr/sap/<SID> mount point will also be used to store local SAP executables. This prevents problems with busy mount points during database package shutdown. Due to the size of the directory content, it should not be part of the local root file system. The /usr/sap/tmp might or might not be part of the root file system. This is the working directory of the operating system collector process saposcol. The size of this directory will rarely be beyond a few Megabytes.

If you have more than one system, place /usr/sap/put on separate volume groups created on shared drives. The directory should not be added to any package. This ensures that they are independent from any SAP WAS system and you can mount them on any host by hand if needed.

All filesystems mounted below /export are part of HA NFS cross-mounting via automounter. The automounter uses virtual IP addresses to access the HA NFS directories via the path that comes without the /export prefix. This ensures that the directories are quickly available after a switchover. The cross-mounting allows coexistence of NFS server and NFS client processes on nodes within the cluster.

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:

•/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 (optional for kernel 7.x and higher)

•/usr/sap/tmp — the directory in which the SAP operating system collector keeps monitoring data of the local operating system

•/usr/sap/hostctrl — the directory in which SAP control services for the local host are kept (kernel 7.x and higher)

24 Planning the Storage Layout