With vmware and virtualisation it seems common to have both a cluster setup (high availability) and then also replicate all systems from a production SAN to a DR SAN. As I am not a network tech I am a bit confused how and what each is protecting against.
Is the cluster setup in your production SAN to protect against certain types of failure, and the DR SAN to protect against different types of failure? Can you give a laymans guide to what kind of disasters the local cluster setup saves you from - and what the DR SAN replicated setup saves you from?
I wasnt sure if you can have an overly complex setup, whereby if production host XYZ goes down, does another host in the cluster kick in to save the day - or does the repliated server on the DR SAN kick in to save the day? I assume the cluster and replicated copy are designed for specific types of failure - but I wasnt sure what.