Currently we have an old ultrasparc that is handling all of the email for
our sites (about 20,000 accounts). Unfortunately, it is overworked,
underpowered and in definate need of replacement.
There are currently two lines of options on how to replace this server:
1) Get a _really_ big machine with plenty of horsepower, memory and fast
disk (RAID of some kind).
or
2) Get three solid Alpha machines and find some way to make them all as a
conglomeration take over the duties.
However, it's this second option, which has the benefit of being cheap,
simple for the pointy-haired managers to grasp ("the mail server's
overloaded? add another box!") and scalable, that has grabbed a lot of
attention.
My concern is how to best facilitate a multi-server mail site. I'm
worried about issues of keeping all of the users' data straight while
still maintaining a sane management protocol.
Currently, these are my thoughts on ways to do this:
1) NFS mount the mail spool on all the machines and use round-robin DNS
and/or a Cisco local-director to load balance the incoming POP and SMTP
connections and some kind of a batch job to sync the /etc/passwd files. I
am worried about lock files here, though, and what might happen if things
get fouled up, or if the host NFS machine went down.
2) Divy the users around by domain name. Foo.com goes here, bar.com goes
there, etc. This is simple, but a headache to manage due to poor
domain<->user association records that have been kept in the past and the
need for some kind of centralized management tools.
3) Use some kind of a low-end NetApp and RR-DNS. My understanding is
that netapp's NFS system is much better than standard implementations and
would be able to prevent the possible locking problems.
4) SMTP comes in on one machine only. POP requests are handled by a
different machine. Scale the machines upwards as needed. Drawback here
is the scalability of the machines.
--
I apologize for the length of this. I posted it here due to the good
responses that are generated, and because we plan to use Alpha clones
running 4.0D, so there may be some DU-specific things that would be
useful.
Thanks so much.
=-=-=-=-=-=
Robert Hayden rhayden_at_means.net UIN: 3937211
IP Network Administrator http://rhayden.means.net
MEANS Telcom (612) 230-4416
Received on Wed Apr 08 1998 - 20:55:26 NZST