Cyrus 2.3.7 Replication Question

Robert Mueller robm at
Wed Jul 12 20:31:12 EDT 2006

> Can you detail this A <-> B replication setup more? I've been trying to
> figure out how to make use of the new 2.3.7 replication features outside 
> of a murder. The thing I can't wrap my head around is the following 
> situation:
> 1) Server A dies
> 2) Users are sent to Server B via DNS redirects
> 3) Server A is restored
> 4) Mailboxes on Server B are now more 'current' than mailboxes on Server A
> In other words, the failover is easy(ish) but the failback has me 
> scratching my head. I Think two way replication solves that.

Once you've got Server A back, you have to make sure that when you start it 
you've disabled the sync_client and all IMAP/POP/LMTP connections to Server 
A, otherwise if you have things happening to both of them at the same time, 
you'll be in big trouble since there won't be an "authorative" server 

Before you change back to the original setup, you have to change the 
configuration so that Server B has a sync_client and Server A has a 
sync_server, and run replication back the other way until all the mailboxes 
on Server A are back up to date with the contents of Server B (and probably 
for safety do a sync_client -u on each user), then switch over back to the 
original setup.

Basically, it's not a "simple and quick" process from what I can see. Maybe 
David Carter (who developed the replication code) can add any comments?


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