Hi spambox,
why having 3 LDAP with different information ?
why not 1 with all info and a failover ?
your "very big storage" is a on a cluster file system (perhaps ocfs2)?
each node could then write and read.
each node has same information and could handle all stuff that is
derived by loadbalancer.
there is no need to switch over and mount
|-------------|
| postfix1 | very big storage
| imap1 |-------------|********************
| | | *
|-------------| | *
| | *
| | ocfs2 *
|-------------| | *
| postfix2 | | *
| imap2 |-------------| /srv/maildirs *
| | | *
|-------------| | *
| | *
| | *
|-------------| | *
| postfixn | | *
| imapn |------|------|********************
| | |
|-------------| |
|
|
|-------------| | |-------------|
| | | | |
| LDAP1 |------|------| LDAP2 |
| | | |
|-------------| |-------------|
Each node is able to comm with LDAP
If a node fails, then loadbalancer transmit requests to left over nodes.
I don't know if you can live with a master/slave LDAP configuration, but
I think this should do it.
I'm using postfix with VDA patch, vmail user, courier-imap, but MySQL as
backend cause of "postfixAdmin"
Kind Regards
Chris
spambox schrieb:
> Hello everyone.
>
> This is my first question here so please forgive me if i'm out of topic or
> something...
>
>
> I'm building up this architecture with postfix + ldap + Courier IMAP
> (i hope the below ascii art is displaying correctly :)
>
>
>
> |-------------|
> | postfix1 | very big storage
> | LDAP1 |-------------|********************
> | server1 | | *
> |-------------| | /home1 *
> | | *
> | |-------------------*
> |-------------| | *
> | postfix2 | | *
> | LDAP2 |-------------| /home2 *
> | server2 | | *
> |-------------| | *
> | |-------------------*
> | | *
> |-------------| | /home3 *
> | postfix3 | | *
> | LDAP3 |-------------|********************
> | server3 |
> |-------------|
>
>
>
>
> Now, let me explain how this is going to work.
> This architecture works with Qmail+Ldap and now i'm migrating to PostFix
> (for many reason)
>
> server1,2,3 have 1 balancer in front which simply redistribute the traffinc
> among the 3 servers.
>
> 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.
>
> Each LDAP have list of his users. For each LDAP entry we have a record
> telling us, who is the MailServer 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.
>
>
>
> Now, i've a couple of questione here.
>
>
> 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 wont be able to install 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?
>
>
> Thank you very much for your time and for any tip or advice.
>
> Good bye everyone.
>
>
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