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

Cluster conversion for existing instances
The recommended approach to clustering SAP configurations with Serviceguard is described in
“Installation options” (page 44), “SAP installation (Phase 2)” (page 58), “Post SAP installation
tasks and final node synchronization (Phase 3a)” (page 59), and “Completing SGeSAP package
creation (Phase 3b)” (page 64) sections. The basic goal is to initially setup a “cluster-aware”
environment and then install SAP using virtual hostnames and the appropriate storage layout. There
might be configurations though, where the cluster conversion of an existing SAP instance or database
is necessary in order to make it high available with SGeSAP.
Such a cluster conversion consists primarily of two tasks:
• Separating and moving the SAP instance files/file systems to file systems categorized as “local”
copies, as “shared exclusive” or as “shared nfs” file systems as described in chapter 4 “SAP
cluster storage layout planning” (page 30). This might involve creating new volume groups
and logical volumes as well as copying the instance files from the current file system to the
newly generated ones. This step is usually straight-forward and will not be covered here.
• Adapting each occurrence of the old instance hostname with the new instance virtual hostname.
This concerns filenames as well as configuration values containing hostname strings in the
files. For a Java based instances, this will also require the use of the SAP “configtool”.
The cluster conversion of a central instance (DVEBMGS with Message and Enqueue Server) into
a System Central Services (ASCS) instance and Enqueue Replication Service (ERS) Instance is not
covered here. SAP Note 821904 has details on how to accomplish such a conversion and/or the
reinstallation of instances using the High Availability installation option of the SAP sapinst
command.
Converting an existing SAP instance
• Adapt the SAP instance profile names by renaming SID_Instance_oldhost to
SID_Instance_newvirthost
• SAP profile names will also referenced in the SAP start profile of the instance. In the SAP start
profile look for _PF = or _PFL = entries and change the right hand side accordingly.
• Adapt all SAP profile entries referencing the old hostname of the converted instance. These
depend on the type of instance. Possible profile entries might be:
◦ SCSHOST
◦ j2ee/scs/host
◦ enque/serverhost
◦ rdisp/mshost
• The SAPGUI also contains connect strings referencing oldhost. These must be converted to the
newvirthost names.
• Change properties Java instance referencing the old host using the configtool.
78 Clustering SAP using SGeSAP packages