Managing HP Serviceguard Extension for SAP for Linux, December 2013

If you have more than one system, place /usr/sap/put on separate volume groups created on
shared drives. The directory must not be added to any package. This ensures that they are
independent from any SAP Netweaver system and you can mount them on any host by hand if
needed.
All files systems mounted below /export are part of NFS cross-mounts used by the automount
program. The automount program uses virtual IP addresses to access the NFS directories via the
path that comes without the /export prefix. Three components must be configured for NFS toolkit:
• The NFS server consisting of a virtual hostname, storage volumes and mount points in the
/export directory
• The NFS server export table consisting of a list of NFS exported file systems, export options
and NFS client access control. Note: The specification of the fsid export option is key as it
ensures that the device minor number is retained during the failover to an adoptive node.
• The automount configuration on each adoptive node, consisting of a list of NFS client mount
points
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.
Special attention needs to be given to the diagnostic agent (DA) instance directory if a related
dialog instance (both using the same virtual hostname) is planned to be clustered. Such DA instances
need to move with the related dialog instances. Therefore, their instance directory has to be part
of the package. It is recommended that the DA instance filesystem resides on the volume group of
the dialog instance (not on a volume group common to all DA instances).
The SYS directory of the DA SID requires special attention. The DA installation does not create
links underneath SYS as the standard Netweaver installation does, but just creates this directory
on the local filesystem. To keep a central and consistent copy of this SYS directory within the cluster,
it is recommend to manually create a similar setup as with a Netweaver installation (SYS containing
links into /sapmnt and /sapmnt itself mounted to an exported directory). For more details on
the preparation steps, see Chapter 5, “Clustering SAP Netweaver using SGeSAP packages” (page
49). If each cluster node has local dialog instances installed and therefore there is a DA SYS
directory on each node, the /sapmnt approach is not necessary.
4.1.2 Option 2: SGeSAP NFS idle standby cluster
This option has a simple setup, but is limited in flexibility. It is recommended to follow option 1 for
most of the cases. 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). Application
Server Instances are not installed on cluster nodes. Replicated Enqueue is not used.
• Additional SAP software is not installed on the cluster nodes.
The use of a NFS toolkit 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.
4.1.2.1 Common directories that are kept local
For information on common directories that are kept local, see Table 4 (page 38)
Local database client software needs to be stored locally on each node. Details can be found in
the database sections below.
Parts of the content of the local group of directories must be synchronized manually between all
the nodes in the cluster.
4.1 SAP Instance storage considerations 41