I have a task where I need to build a failover cluster in two cases: first with servers on Red Hat Enterprise 5.1 and second with SUSE Linux Enterprise 11 SP1. Both cases have SAN. I know there are many ways to build failover cluster, but I can’t find out more, so I need next:

• The ways to build it? I know only virtualization.
• Any good book or resource to broad my mind?
• I’ll be glad to hear any suggestion.

Thanks!

EDIT #1: failover of servers with bussiness application on it.

EDIT #2: will be great to hear summary about solutions with SLES servers?

EDIT #3: So if I understand correctly, in my cases the main ways are to use internal solutions or virtualization. So now I have additional questions:

1. Does manufacturer of blades provide some solution? For example HP or IBM.
2. (Without virtualization) Do I need additional server to control "heartbeat" between main and redundant servers?
3. (Virtualization) For example I have several physical servers with VMs. Do I need additional server to control availability of VMs and to move VMs to another physical server in the case their physical server failure?

Sorry for my poor English.

EDIT #4: Failover of VM or OS on physical server. In both cases will be used SAN , it's not specified, but I think with file system image on it. I started to think that my question is stupid and I need to remake it.