Re: Hyper spaghetti
How about ZFS or another filesystem with snapshotting built-in ?
The problem is with applications keeping the files open / buffers needing flushed.
VMware has a button on the snapshot window to "quiesce guest filesystem", which forces it to flush the buffers, but won't write any application state out to the drives. In general you'll get away with re-running transaction logs to get databases (including Exchange Server) up-to-date. Personally I never ran into a problem with it (a bit further down the road I deployed file-level backups using Bacula which meant that those were closed, flushed and safe), but there are certainly situations where it would be a Bad Thing™.
Did I use it in the past to cover backups for several small businesses? Yes, I did. Was there ever a problem restoring files? No, there was not. Would I use it for a server handling hundreds of users? No, I wouldn't.