We have an legacy but very important app running on windows server 2003. App itself doesn't support any kind of HA and it's not the most reliable piece of software. Last week we had a special emergency when OS on application server crashed and it didn't go up again.
As far as I know when you use vmware HA the vmware keeps running two VM's which are perfect copies and are totally synchronized. So I wonder what happens if app or os crashes in one copy of VM, does this mean that it also crashes in another ? But in this case HA doesn't make any sense. How about OS updates if one update breaks the app ?
Can you please enlighten me on how does relly work this vmware HA and what against it protects.
Thank you very much.