HP Serviceguard Extension for SAP (SGeSAP) manual Single MDM Serviceguard Package ONE, Opt/MDM

/opt/MDM

The /opt/MDM mount point is used for storing the binaries of the MDM servers. These are static files installed once during the installation. In this specific cluster configuration each cluster node had it's own copy of the /opt/MDM file system. The/opt/MDM only contains a few files and because of it's small size, a separate storage volume / mount point was not created but instead kept in the existing /opt directory. The disadvantage here is a copy has to be maintained (for each software installation) on each cluster member. From a system management an alternative approach would be to configure /opt/MDM as an NFS file system.

Single or Multiple MDM Serviceguard Package Configurations

MDM with SGeSAP can be configured to run either as a "Single" Serviceguard package (ONE package) OR as "Multiple" Serviceguard packages (FOUR+ONE).

Single MDM Serviceguard Package (ONE)

•In the case of "Single" MDM Serviceguard package all four MDM components (mdb mds mdis mdss) are always started and stopped together on "one" cluster node - the node on which the Serviceguard package itself is started or stopped on. All four MDM components are combined or grouped together.

This is also is reflected in the name for this Serviceguard package name called mgroupMDM.

•The naming convention for the Serviceguard packages is: mgroupID - the string "mgroup" stands for mdm grouped components and is required; the string ID is used as a placeholder for a xx System ID and can be set to any value.

•The mgroupMDM package contains code for dependency checks: it will ensure that the MDM components

are started and stopped in the correct order: mdb -> mds -> mdis -> mdss - and in the reverse order for stop.

•The advantage of the Single MDM Serviceguard package is a simpler setup - less steps are involved in setting up and running the configuration - but with the limitation that all four MDM server components always have to run together on the same cluster node.

Multiple MDM Serviceguard packages (FOUR+ONE)

•In the case of "Multiple" MDM Serviceguard packages each of the four MDM component (mdb, mds, mdis and mdss) is configured and run in a separate (mdbMDM, mdsMDM, mdssMDM, mdisMDM) Serviceguard package. So in the case of a four node cluster each MDM Serviceguard package could be configured to run on it's own cluster node and by this distribute load over the four cluster nodes.

•The naming convention for the Serviceguard packages is: mdbMDM - the string mdb stands for mdm database components and is required; the string MDM is used as a placeholder for a System ID and can be set to any value. The name of the other Serviceguard packages is derived from: mds stands for MDM master data server components, mdis stands for MDM import server components and mdss stands for MDM syndication server components.

•A "fifth" Serviceguard package called masterMDM must also be configured for this configuration type. It will be used to ensure that cluster-wide the four MDM Serviceguard packages are started in the correct order: mdbMDM -> mdsMDM -> mdisMDM -> mdssMDM regardless of on which cluster node they are started. The same is true for stopping the packages - the reverse order will be used.

•The advantage of Multiple MDM Serviceguard packages is flexibility: it is possible to balance the load by distributing the MDM servers over cluster nodes - but with the cost of requiring more steps to install and run the system.

Setup Step: MDM010

Add MDM virtual IP addresses and hostnames to /etc/hosts.

The database will be accessible under the 172.16.11.97/mdbreloc virtual IP address/hostname, the MDS component under the 172.16.11.95/mdsreloc virtual IP address/hostname and the MDM NFS files systems under 172.16.11.95/mdmnfsreloc virtual IP address/hostname. MDIS and MDSS do not require a separate virtual address. Both always connect to the virtual IP address of the MDS server. A virtual IP address will be enabled on the cluster node where the corresponding Serviceguard package is started and disabled when the package is stopped.

114 SAP Master Data Management (MDM)