On Mon, 10 May 2010 01:00:29 -0430
Jose Ildefonso Camargo Tolosa <[email protected]> wrote:

> Hi!
> 
> Yes, I know, this is kinda off-topic, but looks interesting.

Thank you for your interest!

> > |-------------|
> > |   postfix1  |               very big storage
> > |   LDAP1     |-------------|********************
> > |   server1   |             |                   *
> > |-------------|             |   /home1          *
> >       |                     |                   *
> >       |                     |-------------------*
> > |-------------|             |                   *
> > |   postfix2  |             |                   *
> > |   LDAP2     |-------------|   /home2          *
> > |   server2   |             |                   *
> > |-------------|             |                   *
> >       |                     |-------------------*
> >       |                     |                   *
> > |-------------|             |   /home3          *
> > |   postfix3  |             |                   *
> > |   LDAP3     |-------------|********************
> > |   server3   |
> > |-------------|
> >
> >
> >
> >

> Ok, so, load balancing here, with different homes for each server, so,
> each server have its own "set of users", right?

Yes, each LDAP have list of his users. For each LDAP entry we have a record 
telling us, who is the Mail server for that user. So if the balancer send user 
"test" to mail server1 and from the LDAP we see that "test" user belong to 
server1 then "test" request is served, ELSE if user "test" has mail server set 
on "mailserver3" for example, the request is redirect to mailserver3 that will 
handle his request.

 
> >
> > if one server goes down, the one next to him will Up his ip address and 
> > mount his partition on the storage untill the server restarts correctly.
> 
> Now, this is more typical of HA clusters, what gets me confused is
> what I asked on the last question, so, when say, server 1 goes down,
> server 2 mount server1's home partition and start getting mails (and
> serving IMAP requests) as if it were server1, right? I'll reserve my
> other comments until I get more information on this.

Yes, if server1 goes down the cluster will mount up server1 interface and home 
partition on server2. Server2 will temporarily act as server1 and server2 
untill server1 is back on line.




> > 1) I've never used Courier IMAP, but reading on the internet i've found 
> > that it use gethostbyname() to resolve and this may cause an infinite loop 
> > for a host with 2 interface but one hostname if one server goes down.
> > So, i'm afraid that i will be able to installa courier-imap on each server 
> > and this will cause a big problem to the scalability of the system.
> >
> > 2) Has anyone ever tryed something like this and its ablet to redirect me 
> > to some good documentation?
>
> I don't use Courier (several reasons, off-topic here), I use Dovecot
> (I can even use SASL from Dovecot to authenticate Postifx's smtp,
> really handy along with reject_authenticated_sender_login_mismatch and
> smtpd_sender_login_maps on ldap).

Nice, i gave a look to this Dovecot and its looks pretty nice! i'vent tested it 
yet but it seems it can be a valid alternative. Im trying to move from Qmail to 
postfix because Qmail is patch-project(dead), while i think Postfix is a valid 
alternative that will make life a lot easyer.




-- 
spambox <[email protected]>

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