Managing Serviceguard Extension for SAP Version A.06.00 for Linux, December 2012

Solutionmanager diagnostic agent file system preparations related to NFS toolkit
If a dialog instance with a virtual hostname is installed initially and clustering the instance is done
later, then some steps related to the file system layout must be performed before the SAP installation
starts.
These steps are optional if:
• It is planned to keep all the diagnostic agent installations on the “local” file system or
• The agent is not configured to move with the related dialog instance.
The SAP installation installs a separate diagnostic agent instance for each host of a dialog instance
installation (physical and virtual). Therefore, diagnostic agent and dialog instances are “linked”
via the virtual hostname and shares the same IP address. As a result of this “link”, an agent instance
must move with the related (clustered) dialog instances, if the dialog instances fail over. As described
in chapter 4 “SAP cluster storage layout planning” (page 30), the logical volume of the diagnostic
agent also has to fail over.
There is also a SYS directory underneath /usr/sap/DASID. Compared to other SAP installations
this does not contain links to /sapmnt. To have the same diagnostic agent SYS available on all
the cluster nodes, these links must be created and subsequently the /sapmnt/DASID must be
mapped to a NFS-exported directory.
The steps to install file system layout are as follows:
1. Create directory /sapmnt/DASID.
2. Create a link from /usr/sap/DASID/SYS to /sapmnt/DASID.
3. Create a logical volume and filesystem for the files on /sapmnt/DASID.
4. Mount that file system to /export/sapmnt/DASID (create this directory if it doesn’t exist
yet) and export it via NFS.
5. Mount the exported filesystem to /sapmnt/DASID.
To make this exported filesystem highly available, the same mechanism as for other SAP SIDs can
be used.
1. Add the exported file system together with its volume_group, logical volume, and file system
mountpoints to a NFS toolkit package.
2. Add /sapmnt/DASID to the automount configuration.
3. Mountpoint /export/sapmnt/DASID must be available on all the cluster nodes where the
NFS toolkit package runs. /sapmnt/DASID must be available on all the nodes where the
dialog instances run.
Intermediate node sync and verification
For more information about synchronization of the other cluster nodes with the automount
configuration, see “Post SAP installation tasks and final node synchronization (Phase 3a)” (page
59) section.
It is possible to perform intermediate synchronization to test the NFS configuration.
For more information on synchronization with the other cluster nodes, see “NFS and automount
synchronization” (page 63) section.
Verification step(s):
52 Clustering SAP using SGeSAP packages