On Wednesday 21 June 2006 08:54, Dogsbody wrote:
> >>Surely if you get to this stage then you may as well invest
> >>is some proper dedicated high-availability servers with load
> >>balancers? for each of your services!?
> >
> > Load balancing is not the problem ... the data needs to sync ... and
> > these are mail servers, which makes it interesting ;)
>
> Load balancing isn't just about connectivity, they are great for redundancy
> too as you can bring servers up and down behind a load balancer without
> things borking. HTTP is by the far the easiest as it is stateless but
> e-mail (IMAP, POP3) and other protocols work fine too. The hard part is
> knowing where to stop...
>
> Multiple ISP connections (multihomed)
> into multiple firewalls
> into multiple load balancers
> into multiple mail servers
> reading off multiple file servers
> with multiple PSU's in each box
> running from multiple mains feeds
> ... etc. etc. ... :-)
>
> God, if only I had the money, I would love to play with this sort of stuff!
> :-)
>
> Dan
Very true Dan, but with just "mail", it should be fairly simple to have the
actual mail stored on an external drive - and then simply mount that drive to
each system that "needs" access to mail. You then simply move the DNS to the
active machine or even have them both work together. While problematic with
pop3 and qpopper because of the lock files, with Maildir and something like
courier-imap (which does both imap and pop protocols) it is actually quite
simple and works well.
--
Larry Smith
SysAd ECSIS.NET
sysad (at mark) ecsis.net