On Mon, 2009-07-27 at 10:22 -0700, Seth Mattinen wrote:
Ed W wrote:
I think there is a whitepaper from Dovecot's current main sponsor (before they were called Rackspace) which described their architecture using pairs of servers and DRBD between them. Each server is moderately loaded and active. If one server fails then half the users don't notice and the other half get switched over to what is really their slave server.
The whitepaper is pretty outdated, I don't think we want to show it to people anymore. :)
Seemed like an elegant architecture...
It's stupidly simple but it works. If you have two spare systems to make a lab out of you'll be surprised how easy it really is. The only thing I hate about it is the idle slave hardware just because I feed bad about powerful machines sitting around waiting for something to happen.
Another possibility is to do cross-replication, i.e. server a is replicating to b, and b is replicating to a. The problem with that is that if either one breaks, the other server now handles twice the number of users..