[imp] load balancing

[Andrew Morgan]

On Thu, 5 Dec 2002, Liam Hoekenga wrote:

> Hey guys -
>
> We've got nine machines dedicated to webmail (Horde/IMP/Turba) in our
> server farm.  We're currently distributing the load between them using
> sort of "round robin" technique - we're not actually using round robin
> DNS, rather redirects from a central "gateway" (mail.umich.edu) to one of
> the nine hosts.  This worked ok when our service was starting up, but our
> audience has grown considerably (we had 38,000 unique users last month and
> 51,000 since we moved our webmail to IMP 3.x in January), and we're
> considering alternatives.
>
> We're looking for something to more efficiently distribute the load
> amongst the servers.  We do have busy times of day, but all of the
> machines get hugely loaded at the same time.  We may have a load of > 20
> on 3 machines, but have a load of < 1 on the other 6.
>
> What are people using for load balancers?

Wow, that's a big deployment!  We've got two Dell 2650 servers running
Debian 3.0 and using Horde 2.1, IMP 3.1, and Turba 1.1.  We have a Foundry
Networks ServerIronXL load balancer.  I don't know a whole lot about it,
but we bought the gigabit uplink module, and it has 8 available ports for
load balancing.  I don't know if they make a model with more ports.

Let me know if you want any more information.

	Andy