>I have a question about qmail regarding its mail handling capacity.....
>How many remote emails can qmail send simulataneously, assuming it is run
>on a Dual-CPU PIII 500Mhz with 512Mb RAM and a SCSI hard disk? The internet
>bandwidth is 10 Mbps.
On a dual celeron 466 with 512Mb ram. and 3 10k scsi drives (one for
/var/qmail/queue, one for /var/log, one for /usr/home)
concurrency remote at 500
concurrency local at 50
FreeBSD 3.4-S
localhost dnscache
It will push 12 Million on a good day. (4% local delivery).
This is qmail 1.03 + big-todo + big-concurrency + qmailqueue
>What is the general number of emails that a machine with the above
>specifications can send per second/hour/day? How do I fine-tune it to send
>off millions? I only know of changing the "concurrencyremote" figure in
>/var/qmail/control/concurrencyremote. I set it to 100 for testing. What
>should be a good figure assuming that I will do free email hosting on the
>server for hundreds of thousands of users?
whoa there...hundreds of thousands of users? You are going to need much
better disk performance than one scsi disk will give you. More info below
>I have also noticed that some free email services like Yahoo also uses
>QMail (if I'm not mistaken). They have millions of users, so I assume they
>host the email service on multiple machines.
I think that's a safe bet.
>How is it possible to do
>load-balancing for emails on multiple machines? 'cause everyone will have
>an email address like [EMAIL PROTECTED], but how does Yahoo redirect
>portions of users to different machines for mail receival/sending?
Well, I don't work at yahoo, but off the top of my head something like this
comes to mind:
nfs1.dom.com has a large, fast raid array attached to it.
smtp1.dom.com smtp2.dom.com smtp3.dom.com ... smtpn.dom.com
are all servers running qmail/qmail-smtpd. There are set up to do local
delivery to maildirs in /usr/home/popuser (For more information on running
multiple pop boxes under one UID, follow some links on the qmail home page
(like vpopmail and pop toaster).
/usr/home/popuser is mounted via nfs from the machine nfs1.dom.com via a
separate 100mbit ethernet segment.
pop1.dom.com pop2.dom.com pop3.dom.com ... popn.dom.com
are all servers running qmail-pop3d and friends... There serve the pop boxes
from /usr/home/popuser, which they mount from nfs1.dom.com
smtp.dom.com points to smtp1, smtp2, smtp3 ...
pop.dom.com points to pop1, pop2, pop3 ...
That setup should be able to scale pretty well, as long as the NFS box is up
to the challenge...
(quad zeon connected to 3 firewire raid 5 arrays and running software raid 0
over them? :D)
This sound reasonably to the rest of you?
Matthew B. Henniges
CoPresident
Axl.net Communications
http://www.axl.net
(203) 552-1714
