Managing Serviceguard Extension for SAP, December 2007

Planning the Storage Layout
SAP Instance Storage Considerations
Chapter 2 51
Each filesystem that gets added to a system by SAP installation routines
needs to be classified and a decision has to be made:
• Whether it needs to be kept as a local copy on internal disks of each
node of the cluster.
• Whether it needs to be shared on a SAN storage device to allow
failover and exclusive activation.
• Whether it needs to provide shared access to more than one node of
the cluster at the same time.
NOTE SGeSAP packages and service monitors require SAP tools. Patching the
SAP kernel sometimes also patches SAP tools. Depending on what SAP
changed, this might introduce additional dependencies on shared
libraries that weren’t required before the patch. Depending on the
SHLIB_PATH settings of the root user it might no longer be possible for
SGeSAP to execute the SAP tools after applying the patch. The
introduced additional libraries are not found. Creating local copies of the
complete central executable directory prevents this issue.
The following sections detail the three different storage options.
3 - SGeSAP CFS
Cluster
combines maximum flexibility with the convenience of a Cluster
File System. It is the most advanced option. CFS should be used
with SAP if available. The HP Serviceguard Cluster File System
requires a set of multi-node packages. The number of packages
varies with the number of disk groups and mountpoints for
Cluster File Systems. This can be a limiting factor for highly
consolidated SGeSAP environments.
Table 2-1 Option descriptions (Continued)
Option: Description