Cyrus IMAP and MySQL mailboxes (Building load-balancing cluster)

[Igor Zhbanov]

2006/11/17, Bron Gondwana <brong at fastmail.fm>:
> On Fri, Nov 17, 2006 at 11:54:39AM +1000, Sarah Walters wrote:
> > Why don't you look at throwing two beefy boxes at this problem in a
> > hot-spare
> > configuration? Have a single large box managing the mail and a heartbeat
> > so
> > that if one goes down the other immediately takes over its IP and just
> > keeps
> > going? You will lose anything that is actually in memory, but that
> > shouldn't
> > be an issue as long as you are using a SAN and immediately committing to
> > disk
> > rather than using a solution like MySQL. There is no need for load
> > balancing
> > here as far as I can tell, and what you lose in having to buy a chunkier
> > server
> > you will gain in reduced power consumption and associated data centre
> > costs.
>
> That doesn't scale forever unfortunately, though you can get pretty
> beefy, eventually you need to scale sideways.  Once you're scaling to
> multiple machines you need a proxying frontend of some sort (murder or
> our perdition/nginx solution, take your pick) and this all becomes a lot
> easier.
>
> Also it means you don't have hot spare hardware (or cold spare hardware)
> sitting in your datacentre doing nothing if you're willing to take the
> time to make multiple cyrus instances work on the same machine.  Then
> you can have both masters and replicas on the same host, and just switch
> one up to be a master when the other dies.

I have thought about LVS (Linux Virtual Server) load-balancer. As I
understand, having some kind of shared storage, I can build system
without spare servers. All frontends will be equal to each other. And
all of them will be loaded equally by load-balancer.