SAP CRM 2007 installation in cluster

Dear Experts,

We are about to start the installation of CRM 2007 (ABAP+JAVA) with

Oracle 10g on Windows x64 in cluster environment. In the SAPINST dialog

box under High availability option, I could see installation options like ASCS

Instance, SCS Instance, First MSCS node, Database Instance, Additional

MSCS Node, Enqueue Replication Server, Central Instance and Dialog

Instance.

I have gone through the installation guide. I have below queries

regarding the same. Can you please clarify the same

1) Our requirement is we want to have an ACTIVE-ACTIVE cluster setup

with sap service running in Node A and Database running in Node B. Can

we have this setup in ABAP+JAVA setup

2) Also,in the SAPINST dialog box as said above except last two

(Central and Dialoge instance) as per standard installation guide are

to be installed in shared drives as per the requirement. But, central

and dialog are said to be installed locally on any one node in MSCS or

in separate server. As per my understanding Dialog instance will be

used for load balancing which we do not require now. Hence I feel this

is optional in our case. Where as Central Instance I am not able to

understand why this option is for? Is it mandatory to be installed or optional. If

so, when I installed it in one of the MSCS node the incase of failover

how does it effect the system. As per my understanding ASCS and SCS

comprise central instance.

Please clarify and thanks in advance.

Regards,

Sharath Babu M

+91-9003072891