Switching replication servers

[Jérôme NENERT]

Hello,

I had 2 imap servers, imap1 and imap2.
imap1 was the master
imap2 was the slave

I try to switch the 2 servers ( to be able to connect users to the slave 
if something goes wrong on the master ):
imap2 become the master
imap1 become the slave

But replication doesn't work.
Can't see nothing in logs.
Tried to remove any sync log et master_uuid file on both servers, but 
doesn't work either.

Any idea about how to switch ?

Another question: what is replicated by the sync protocol ? ( the spool 
and the user directory are, but what else  ?? )

Regards.
Jerome