If you want to run different applications that reference them on both servers then you are not really in a cluster any more. The service that is protected by being in a cluster with consist of resources to be available, typically disk, IP address and service processes.
These resources in a standard cluster are only available on one node at a time, and for good reason. If you have people connecting to the standby server directly, then they need to be prevented from accessing the services being protected by your cluster.
You might have an Active-Active configuration, but this is really two discreet sets of services being protected by two clusters, but using the same hardware. The only exception to this would be a true database cluster such as Oracle RAC which truly shares the disk and offers services on both sides.
If you really need to provide what you describe, you could:-
- Manage the disk as a cluster service, with it's own IP address and the NFS server included with node 1 active and node 2 standby
- Manage your 1st business service with node 1 active and node 2 standby, mounting the disk with NFS from the IP address above.
- Manage your 2nd business service with node 1 standby and node 2 active, mounting the disk with NFS from the IP address above.
You will need to stop people referring to the disk directly and get them to use the NFS mounted view.
I think that this would give you something nearer what you need. If node 1 were to fail, then the services running on node 2 would remain but you would lose the NFS disks until node 2 detected that node 1 had failed and brought up the disks and NFS to serve itself. At the same time, the business service on node 1 could be brought up on node 2 as they both rely on the NFS mounted disks. It might seem a bit odd to NFS mount to the same server, but that would mean you see the same view from either side.
An alternate would be to have the disks on a physically separate cluster just providing NFS to these two nodes.
It's a shame I don't know how to post a picture to better describe this.
Robin