Hi,

I was checking my HotMail account today, when a thought came to me. How the hell can HotMail have millions of users on a single server? Does anyone know how they do it (and has anyone got a major free email site).

I am assuming this is how they do it:
When you signup for an account, the script checks the HD space of server 1,2,3,4 etc..and finds empty space to create the initial profile.

When you logon to the system (to help speed up everything), a single DB holds your user name, maybe password and which server your email resides on. Then you can log in.

Also, with all these millions of users, there cannot be a single smtp outgoing mail server right? (because it would cause a major overload) So each server also has its own outgoing smtp mail server?

Am I anyway close?

mmm.... well....
There are "non x86" computers...
that can be plugged toghether with 128 or more processors, with terabytes of disc space running fiber optics conections...
you know...

then... think in more than one of this "multiple computers" in a multiple multiple computers environment ... with multiple raid disk configurations and looooots of memory...
you get the idea ?

Just look at this baby...
http://www.sgi.com/origin/3000/

up to 512 processors
up to 1Tb of memory
716Gb/seg. of systems bandwidth

Millons of dollars.....
quinticuasillinios of users :D

Just my 0.02 ...

I had heard that when Microsoft bought HotMail, they tried porting the system to NT servers but were unsuccessful.

Do you think they have 1 computer? :D I don't think so.
It can be huge cluster or a lot of powerful computers:
hotmail.com. 1047 IN A 64.4.53.7
hotmail.com. 1047 IN A 64.4.54.7
hotmail.com. 1047 IN A 64.4.43.7
hotmail.com. 1047 IN A 64.4.44.7
hotmail.com. 1047 IN A 64.4.45.7
hotmail.com. 1047 IN A 64.4.52.7

So as you can see hotmail is on different IPs and probably different machines.
There is also possibility that they have 1 core "router" which accepts all connections and then it is doing the following:

-->Hotmail.com_____/j*@hotmail.com--------/a*@hotmail.com

And so on ;)

So the mails starting from "A" are on one machine and other on others and the main router "Hotmail.com" accepting connections from the net and checking its database to see what goes first in the mail and then forwards it to the server that responsible for it.

Yes I am sure hotmail runs on multiple systems. Also hotmail uses a modified version of QMail.

Wow nice.. Thought it would be like that....

So, has anyone done this? I mean run an email site and have so many users that they use multiple servers?

I think hotmail uses 5000 or so servers, running Unix or Linux.