How to make SAP MDM Highly available and resistant to SPOF

[Former Member]

Hello Experts,

I have to design the architecture for High available SAP MDM system. I am looking for answers to below questions:

1.) To my understanding, with Microsoft Cluster we can address only hardware(Physical Machine) failure or operating system failure, but what will happen if the host is running fine and the MDS installed on the host fails. Do we have a mechanism to avoid downtime other than restarting the MDS.

2.) Is SAP MDM architecture/ installation similar to other SAP system architectures, for eg: will SAP MDM have

Central Instance, Central Services Installation( Message Server and Enqueue Server),Database Instance,Dialog instance

Additional application server instance. Or it has only MDS, MDSS, MDIS and Database

3.) SAP MDM forms a part of Netweaver stack along with other applications like PI , BI etc, Does it mean that we have to install netweaver also before we install SAP MDM or it can be installed independently. I mean how SAP MDM is linked to Netweaver in

landscape.

4.) What is the difference between Switchover Cluster and Software Cluster(Redundant application server) since both of them needs two or more host machines.

Request you to please guide me as I have never worked on MDM System Architecture.

BR

Manoj

[Former Member]

HI Manoj,

First of all i hope you have this guide:

http://www.sdn.sap.com/irj/scn/go/portal/prtroot/docs/library/uuid/206692e2-39e5-2b10-c49d-dce775160...

"How To Cluster MDM 7.1 using MSCS".

And to answer your questions:

1.) To my understanding, with Microsoft Cluster we can address only hardware(Physical Machine) failure or operating system failure, but what will happen if the host is running fine and the MDS installed on the host fails. Do we have a mechanism to avoid downtime other than restarting the MDS.

Yes you are right, but whenever a failover occurs in a MDM cluster environment; MDM Server instance on 2nd machine comes up automatically. The only issue is Repositories get unloaded due to failover. And thats why it looks like all work gets stopped. To overcome a maual intervention, there is a parameter in MDS.INI to automatically load repository whenever MDM server starts after failover. Can go through Guide, but its not a foolproof method yet.

2.) Is SAP MDM architecture/ installation similar to other SAP system architectures, for eg: will SAP MDM have

Central Instance, Central Services Installation( Message Server and Enqueue Server),Database Instance,Dialog instance

Additional application server instance. Or it has only MDS, MDSS, MDIS and Database?

It has only MDS, MDSS, MDIS and Database in active passive cluster environment.

3.) SAP MDM forms a part of Netweaver stack along with other applications like PI , BI etc, Does it mean that we have to install netweaver also before we install SAP MDM or it can be installed independently. I mean how SAP MDM is linked to Netweaver in

landscape.

Independent. Linking to other NetWeaver modules is a separate project/assignment itself for techies .

4.) What is the difference between Switchover Cluster and Software Cluster(Redundant application server) since both of them needs two or more host machines.

No Idea. Most probably a Basis guy can help you more.

BR,

Alok Sharma