Hi Ashun,
It is not as simple as you think to explain here. Ok, i will try to explain in simple terms as much i can.
Lets assume you have 2 node cluster. node1 and node2. Here node1 is one hpux server and node2 is another hpux server. Both server will access a comman storage. Cluster application(SAP in your case) will be installed on comman storage.
MC Service Guard(Cluster software) will be installed on both nodes and this will communicate with each other. Then we need create a package for SAP. Here package means some configuration files which has details like what are the volume group needs to activated, logical volumes, mount points, commands to start/stop the SAP application, ip address for that package and few other details. We need to keep this package configuration files on both nodes.
When we run the package on nodeA, it will activate the VG, mount the logical volumes, then start the SAP application, assigns IP to the package. NodeB will keep communicate with nodeA through cluster software. If anything happen to nodeA(like hardware failure or OS crash) the entire package will be moved to nodeB and the users continue to access SAP. This is possible because the SAP application is installed on comman storage.
Hope this helps upto some extend.
Best wishes,
Ganesh.
