[horde] horde supports load balancing?

[Liam Hoekenga]

> > Can someone confirm that this is possible, and perhaps
> > give real world examples?  Thank you in advance for your time.

Yes, this is possible.  3 of our machines in our pool are answering to one
hostname.  We're using some custom authentication stuff, but the sql based
session handler, and using VFS for attachments has made multihoming a
hostname possible.

> IMHO, session handling shouldn't be necessary.  When the browser does a
> DNS lookup, it's usually only once per session.  So the client would
> only get 1 IP for your server per browser session..

If it were only that easy.  That's how we'd initially tried to deploy IMP
at umich, but we found users were being asked to reauthenticate
frequently.. because their browser had bounced them to another server.

IE is notoriously bad.

You can't count a machine only talking to one host of a multi-homed
service.  Nor should you want to, as I think it would make real load
balancing more difficult.

We ended up assigning each on of our machines it's own name, to ensure
that once a user got bounced to a machine, they stayed there.  We're
pretty happy w/ our naming scheme - obsolete MTAs (eg carrierpigeon,
pneumatictube, ponyexpress, etc).

On the upside, now that we can use the sql based sessionhandler, and a sql
VFS backend for attachments, we're going to be able to move away from the
1 name = 1 server, and collapse our namespace back to a single name.

Liam