Managing Serviceguard Extension for SAP, December 2007

Planning the Storage Layout
SAP Instance Storage Considerations
Chapter 250
SAP Instance Storage Considerations
In general, it is important to stay as close as possible to the original
layout intended by SAP. But certain cluster specific considerations might
suggest a slightly different approach in some cases. SGeSAP supports
various combinations of providing shared access to file systems in the
cluster. The possible storage layout and file system configuration options
include:
Each filesystem that gets added by the SAP installation routines needs
to be classified and a decision has to be made.
Refer to table 2-1 for more information.
Table 2-1 Option descriptions
Option: Description
1 - SGeSAP NFS
Cluster
optimized to provide maximum flexibility. Following the
recommendations given below allows eventual extension of
existing clusters without limitations caused by the cluster.
Another important design goal of SGeSAP option 1 is, that a
redesign of the storage layout is not imperative when adding
additional SAP components later on. Effective change
management is an important aspect for production environments.
The disk layout needs to be as flexible as possible to allow growth
to be done by just adding storage for newly added components. If
the design is planned carefully at the beginning, it is not required
to make changes to already existing file systems. Option 1 is
recommended for environments that implement clusters with
server consolidation if CFS is not available.
2 - SGeSAP NFS Idle
Standby Cluster
optimized to provide maximum simplicity. The option is only
feasible for very simple clusters. It needs to be foreseeable that
their layout and configuration won’t change over time. It comes
with the disadvantage of being locked into restricted
configurations with a single SAP System and idle standby nodes.
HP recommends preferring option 1 in case of uncertainty about
potential future layout changes.