What happens when a server loses all its state?

[Thomas Vinod Johnson]

What is the expected behavior if a server in a ZooKeeper service 
restarts with all its prior state lost? Empirically, everything seems to 
work*.  Is this something that one can count on, as part of ZooKeeper 
design, or are there known conditions under which this could cause 
problems, either liveness or violation of ZooKeeper guarantees?

I'm really most interested in a situation where a single server loses 
state, but insights into issues when more than one server loses state 
and other interesting failure scenarios are appreciated.

Thanks.

* The restarted server appears to catch up to the latest snapshot (from 
the current leader?).