Managing Serviceguard Extension for SAP on Linux (IA64 Integrity and x86_64), February 2008

Step-by-Step Cluster Conversion
SAP Preparation
Chapter 3 101
Replicated Enqueue Conversion
This section describes how a SAP ABAP Central Instance
DVEBMGS<INSTNR> can be converted to use the Enqueue Replication
feature for seamless failover of the Enqueue Service. The whole section
can be skipped if Enqueue Replication is not going to be used for the
ABAP stack. It can also be skipped in case Replicated Enqueue is already
installed. The manual conversion steps can be done for SAP applications
that are based on ABAP kernel 4.6D, 6.20, 6.40 or 7.0. These kernels are
supported on Serviceguard Extension for SAP on Linux with Replicated
Enqueue. As SAP does not deliver installation routines that install
Replicated Enqueue configurations for these releases, a manual
conversion become necessary.
If the SAP installation was done for Netweaver 2004 JAVA-only or
Netweaver 2004s as documented in section ‘SAP Installation
Considerations’, only the second part ‘Creation of Replication Instance’ is
required. The split of the Central Instance is then already effective and a
ASCS instance was created during installation.
Using Replicated Enqueue heavily changes the SAP instance landscape
and increases the resource demand: Two additional SAP instances will
be generated during the splitting procedure. There is a requirement for
at least one additional unique SAP System ID. Unique means, that the
ID is not in use by any other SAP instance of the cluster. There is also a
requirement for one or two additional shared LUNs on the SAN and one
or two additional virtual IP addresses for each subnet. The LUNs need to
have the size that is required for a SAP Instance directory of the targeted
kernel release.