Redundant and Geobalancing setup

[Cedric Malitte]

Hi,

I use dovecot for a long time now, but only as a single isolated server
each time.

I joined a company a few years back. We had trouble with compagnies hosting
our mail, supposedly full redundant and so on.

The company is small, but we have many dealers around the world, and it's
growing.

Mail became the fist choice for clients to contact the dealers.
No mail, and we loose sales.

For now we have a single server ( with a backup ) on east coast.
And sometimes peoples from EU complain about speed.... ah users :)

What I'd like to implement is a redundant system with 2 servers, one in NA,
one in EU.
And I'd also like to be able to add another server if needed on the west
coast.

Idea is, that if a server goes down, the users will be able to still
receive and send mails, and never loose mails.

For geobalacing and failover, I read that I can do it with DNS ( I'm with
easydns ).

I'm at the first stage where I collect informations that I try to
understand and foresee a solution.

First idea is to set up servers with a mysql master, slaves and a glusterfs
in replica mode on the servers.
I tried glusterfs on FreeBSD and OMG, it's slow as hell ! ( well maybe it's
a trouble on the VMs nics )
On centos it's way better.
But I read there might be trouble/index corruption for the mail storage on
"shared" space using maildir.

I also had a look at dsync, but I wonder if it can be used on more than 2
servers.

I found many pages on dovecot clusters using shared storage NFS mounted,
but I feel it's not really what I need as the servers will be in different
datacenters.

So any guide, clue hint would be really appreciated for me to do my
homework !

Regards.

Cedric