[Dovecot] Replication (Re: MySQL as a storage only.?)

[Seth Mattinen]

R A wrote:
> Seth Mattinen wrote:
>> Multiple master in MySQL is still more of a hack. Also, performance
>> for billion-row SQL tables is rather poor for something interactive
>> like clicking on a message in IMAP and expecting it to pop up right away.
>>
>> I'm looking forward to master-master replication. Not SQL though; I
>> can't find the link now but I remember reading about a master-master
>> system that Dovecot would use to sync maildir/dbox over N masters or
>> something. A pool of beefy master-master Dovecots with a load balancer
>> in front of them would be wonderful - I'm not too keen on the "user a
>> goes on server a, user b on server b" system. I'd love to help out but
>> my own development schedule is beyond full at the moment. =)
>>
>> ~Seth
> 
> Well, what I would like to see is multiple servers, where mail can come
> in simultaniously for user a at both server a,b and c. But a user is
> only connected to one server at a time, although it can be any of them.
> DNS would solve this as they all have the name and mx value. The MTA
> issue is trivial to sync mail between them (as long as sieve filters
> isnt used or updated anyway and that has not propagated) but IMAP and
> POP3 would be a bit trickier. No load balancer as say you have one
> server on one isp in canada, one in australia, and one in germany. Say
> the link suddenly go down to the server in australia for an hour, once
> it comes up you want them to resync automatically.
> 
> Basically your not to keen scenario, but worse, as b  can go on a, and
> then next time on b. Which means that a user can do things like delete a
> file twice, move it to two different locations etc. All you have to go
> on would be timestamps to resolve conflicts, so the servers pretty much
> would have to use ntp for this to work.
> 


I found the message: [Dovecot] Replication milestone 1
http://www.dovecot.org/list/dovecot/2008-May/030446.html

This is something I can certainly provide infrastructure for (load 
balancer plus 3 or 4 servers) and possibly throw my hat in as a sponsor. 
But I have no idea how much progress Timo has made on this.

~Seth