[Dovecot] database failover

Trying to get dovecot to _only_ use local copy of database, only querying another database server (same database, just replicated) if local copy is not responding, I have google fu'd a bit and found my only answer in so far as dovecot did this once upon as time, but it was only due to a dovecot bug, that has since been fixed, is that so? The wiki shows no information of failover, just load sharing, or is it an undocumented feature, or can dovecot not do failover, if not, can it be made so?

Trying to cut down on network traffic, postfix does this nicely, I thought dovecot did too.