Check this thead and see if it answers some of your questions:
There are also various other threads concerning the database in a HA setup (just search on the forums).
AS for this I’m not sure.
I think I read something about some kind of queuing if the database is not available. But I couldn’t find it just now. And even if there is, I think it will only be for a limited time.
Maybe other after more realiable information on this
