e-mail server farm question

[Evren Yurtesen]

Chad Leigh -- Shire.Net LLC wrote:

> 
> On May 23, 2006, at 1:35 AM, Evren Yurtesen wrote:
> 
>> Vulpes Velox wrote:
>>
>>> On Mon, 22 May 2006 11:54:02 -0500
>>> Kevin Kinsey <kdk at daleco.biz> wrote:
>>>
>>>>> At 07:17 AM 5/22/2006, Evren Yurtesen wrote:
>>>>>
>>>>>> Hello,
>>>>>>
>>>>>> I was wondering how does services like yahoo mail is storing
>>>>>> e-mails. Somehow the smtp server should know where to deliver
>>>>>> the mail inside the system and webmail should know from which
>>>>>> server to read it from.
>>>>>>
>>>>>> Does anybody have any practical ideas about how it is done?
>>>>>>
>>>>
>>>> Derek Ragona wrote:
>>>> > If you are using sendmail, as most FreeBSD users are, you can
>>>> > check the sendmail.org site for information on mail handling.
>>>> > There are a number of methods that depend on your setup.
>>>> >
>>>>
>>>> Well, it's pretty obvious that they aren't using a stock
>>>> SendMail:
>>>>
>>>> # telnet mx2.mail.yahoo.com 25
>>>> Trying 67.28.113.72...
>>>> Connected to mx2.mail.yahoo.com.
>>>> Escape character is '^]'.
>>>> 220 mta309.mail.re4.yahoo.com ESMTP YSmtp service ready
>>>>
>>>> Short of finding an article written by someone 'in the know',
>>>> or an answer for someone like that, we can only guess.  I'd
>>>> probably start with guessing a big DB on a large SAN;
>>>> which pretty much negates the "which server to read from"
>>>> question (up to a point).  Everything else is pretty
>>>> academic.  SMTP, IMAP, POP.
>>>
>>> Maildir makes it easy to distribute it across multiple machines as
>>> well.
>>
>>
>> What do you mean exactly? distributing 1 user's mails into seperate
>> machines? I didnt understand how Maildir helps to this actually.
>>
> 
> I am not sure anyone was talking about distributing 1 person's mail  
> across separate machines.  The discussion seemed to be how to handle  
> large amounts of mail spread out across machines, which maildir helps  
> with as you can have one or more file servers and lots of consumers  
> (imap/pop) and deliverers (mta) accessing those maildirs on your file  
> servers.  Combine with a backend database of some sort (we use an  ldap 
> db that includes the path for a specific accounts mail) and voilá.
> 
> Chad
> 

Ah sorry, I didnt think it that way for a moment. I thought you meant Maildir
stores mails in seperate files compred to mbox format used by sendmail so...anyhow
my mistake :) But it is possible to make changes to sendmail so that it
will store to different folders also.

I think the conclusion is a database, multiple smtp servers querying database
to see where to forward received e-mails, multiple pop3/imap servers querying
database to see from where to read the e-mails and multiple storage machines.
This way it can scale to an unlimited size.

So it requires a lot of coding :)

Thanks,
Evren