Question about shared maildir storage

[Javier Miguel Rodríguez <javier.miguel@xxxxxxxxxxx>]

Hello

  This is what I already have:

  One of my customers has the following setup for their mail cluster:

  Two dual processors Xeon 3.2 ghz machines, 2 gB ecc ram, RedHat Linux 
Advanced Server 3.0, Veritas Storage Foundation Cluster File System, 
netqmail 1.05+tls+smtp-auth, courier-imap, maildrop is the selected MDA, 
shared storage (3 TB)  via gigabit fabric (HP MSA1000, ultra320 scsi 
disks 144 gB), no local users.

  Both nodes can write concurrently in the shared storage, veritas 
storage foundation allows that. smtp/pop/imap traffic  is layer 3 
balanced and the two boxes can write concurrrently in the maildirs with 
no problem. Everything works as expected, so we have a high availability 
active-active cluster mail ((es)smtp/pop(s)/imap(s)) system.


  The problem:

  They have almost 180.000 users. They use heavily imap, so they have a 
ton of mail stored. They also have dedicated machines for mailing lists 
managers (sympa & mailman). There are some mailing lists with a lot of 
suscribers (90.000+), so when anybody posts to those mailing lists, the 
*same* message gets delivered 90.000 times in our mail cluster. That is 
a lot of (wasted) space


  What I want to acomplish:


    I want to lower the space requeriments caused by the mailing lists 
in our maildirs storage.. But I do not have a clear idea of how to 
accomplish this. These are some random thoughts:

  * Use a MDA with a SQL backend so when the *same* message is 
delivered to thousands of maildirs only one is stored and symbolink 
links are created. When a user deletes this message with his/her MUA, 
delete the symlink. Courier-imap should also be hacked for this.

  * Use a MDA with gzip-enabled maildir message storage. I do not like 
this approach.

  If this is the wrong mailing list for this question, please tell me 
the correct one

  Can qmail-sql help me?

   Thank you for your support