Re: [exim] Which hardware do you use for your installation?

Quoting Lasse Birnbaum Jensen (gymer@???):

> Looking for experience with large exim installations.
> Please answer the questions below:

We recently reworked our mail-setup at the company i work for. And being
an 'open' company, my boss probably won't mind me posting this rought
sketch. Also i wonder if people reading this have any comments on this
setup :)

Numbers are on a daily basis.

> What are the machine specs for you exim installation?

Our mailsetup consists of about 8 separate clusters of servers sharing a
common task dealing with mail ranging from incoming to imap servers.

On the incoming end (mx) we now have about ~5 servers with a single AMD
Opteron 2.8GHz Dual-Core CPU, 4G ram, and just one SATA-II disk as
storage isn't important.

> How many messages does it handle daily?

In a loadbalanced setup, each server handles about ~850.000 messages.
Grand totalling about ~4.300.000 messages combined on the MX'es. They do
this without breaking a sweat, but accepting mail isn't the hardest part.

> What scanning mechanism do you apply?

On a separate filtering platform, consisting of ~7 servers with 2 dual
core CPUs at 3GHz, 4GB ram and again just one disk. We use Amavis in
combination with ClamAV and 2 commercial virusscanners for holding back
the virusses and Exiscan w/ SpamAssassin on separate platform consisting
of ~10, fast CPU servers, for spamscanning.

These filterservers handle ~75% of the traffic coming in at the mx'es.
That's ~530.000 per server, grand total ~3.200.000 meaning about
1.000.000 messages get rejected at the MXes. Either because of
nonexistent addresses or dnsbls and the like.

Spam is either delivered or dropped. We don't bounce spams.

Delivery is done by yet another platform consisting of just ~4 servers
somewhat in the same order of business as above. They get just a mere
~8% of total incoming traffic, ~120.000 deliveries per server, ~350.000
total. Maildirs for the users are stored on NetApp filers.

One big fat tip for you, free of charge:
Exim is not good at dealing with large queues, partly because of the way
it keeps state in the db4 file. That's why almost all these platforms
have their spool in memory and 'message logging' is turned off (-Mvl
doesn't work).

Exim is really great at being flexible. Almost anything you want is
possible in some way or the other. The other MTA's we tried had severe
problems with certain design-specific aspects of our setup.

We call it SWAMP, short for 'Sendmail Wasn't an Acceptable Mail Product'.

I hope this helps :)

Kind regards,
Sander.
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