From: Fergus Donohue (Fergus.Donohue at domain eolach.com)
Date: Thu 31 May 2001 - 12:23:30 IST
Hi Conor,
As Chris said the max simultaneous users is going to be the problem. The
usage pattern will be very different if you're an ISP or if you're a
corperate. You may be able to gauge the numbers based on the number of
modems if we're talking about an ISP. If it's for a corperate where
everyone will leave themselves logged into mail all day the number of
users will be a _lot_ higher.
You have a couple of options on how you could go with this:
(1). A single box with Cyrus (and a very fast disk array) should cope
nicely with the numbers you're talking about assuming 10% online at a
time. This may leave you stuck in future if you need to scale a lot.
(2). An alternative (much along the lines of Chris' suggestion) is as
follows: Have the mailstore on an NFS server (single point of failure)
possibly consider a NetApp. For this to work you'll have to use MailDir
as the mailbox format - this can be used with sendmail, postfix and
qmail (where it originated). Have multiple smtp and imap/pop servers all
talking to the same mailstore. loadbalance using either DNS or if you
really care a dedicated load balancer (F5 etc.) Linux virtual server may
be of use here although I havn't used it in such a configuration.
IO performance is going to probably going to be the bottleneck for mail,
you'll really need to spend money on disks. I'd guess something like 10
spindles should cope but that's really a finger in the air number, you
really need to find out the users/usage patterns.
Regards,
Fergus.
-- Eolach - Ireland's leading Open Source consultancy web: www.eolach.com email: info at domain eolach.com tel: (+353) 1 874 0510 fax: (+353) 1 874 0515 "Wynne, Conor" wrote: > > Morning all, > > I have this dude who has at present an Exchange mail server with about 1200 > users (40 MB each user/ POP3). > > They now want to set up a Linux Cluster (2 nodes) with email server II / > IMAP4 with Proliant servers. > In the beginning there will be about 3000 users (in the end 7000 max.). > Total storage needed in > the beginning 300 to 500 GB. > > Now my question is : What type of solution are we talking about? Will IMAP4 > work with 7000 users? Now I am a TOTAL newbie when it comes to mail so go > easy on me boys and girls. > > Help me ObiWan, > CW > > -- > Irish Linux Users' Group: ilug at domain linux.ie > http://www.linux.ie/mailman/listinfo/ilug for (un)subscription information. > List maintainer: listmaster at domain linux.ie
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