[Date Prev][Date Next] [Thread Prev][Thread Next] [Date Index] [Thread Index]

Re: Documentation of big "mail systems"?

On Wed, 13 Oct 2004 07:18, Stephane Bortzmeyer <bortzmeyer@nic.fr> wrote:
> I'm currently writing a proposal for a webmail service for, say, 50
> 000 to 500 000 users. I'm looking for description of existing "big

50K isn't big by today's standards.

An ISP I used to work for has something like 1,300,000 users.  They have two 
SMTP machines for outbound email which do virus scanning (to stop customers 
from sending viruses).  They have four SMTP machines for inbound mail which 
do anti-spam and virus scanning (RAV anti-virus and Qmail).  Those four 
machines send mail to the back-end machines according to data in OpenLDAP 
(about four slave OpenLDAP servers and one master).  There are six back-end 
machines for mail store that run Qmail for delivery and the Courier POP and 
IMAP servers, all data on user mail directory and password is in LDAP.  The 
back-end servers use ReiserFS mounted noatime for storage.

When a user connects via POP or IMAP they get to a Perdition server, there are 
three Perdition servers behind Cisco LocalDirectors (for reliability and load 
balancing) which proxy IMAP and POP to the correct back-end servers after 
doing an LDAP lookup.  The Perdition server machines also run Apache and IMP 
for webmail, the webmail instance uses Perdition on localhost for IMAP 

The machines are pretty much all Dell servers with 2*2.8GHz P4 CPUs, about 4G 
of RAM, and 4*U160 disks in a RAID-5 array (with one hot spare).

The machines were all running 2.4.2x last time I was there, but they may be 
moving to 2.6.x now.

SAN and NAS are best avoided IMHO.

http://www.coker.com.au/selinux/   My NSA Security Enhanced Linux packages
http://www.coker.com.au/bonnie++/  Bonnie++ hard drive benchmark
http://www.coker.com.au/postal/    Postal SMTP/POP benchmark
http://www.coker.com.au/~russell/  My home page

Reply to: