[Imap-uw] Large Mailboxes, POP and Server Load

[Michael Cashwell]

On Sep 12, 2007, at 8:00 AM, Erik Kangas wrote:

> We have noticed a trend that probably affects other users of UW  
> IMAP.  In particular:
>
> * User with a large inbox (say 10,000 to 50,000 or more messages)
> * Mailbox not checked in some time resulting in the large number of  
> messages
> * User decides to download and delete the email from the mailbox  
> using POP
>
> ... However, we find that invariably when users are in this  
> situation, the POP process eats up significant CPU continuously and  
> drives up the load on the servers very significantly....
>
> Environment:
> * RedHat Enterprise Linux v3 or 4
> * UW IMAP 2006h
> * MIX-formatted folders

On that last point, are you sure the INBOX the mail is being  
delivered to is MIX format? I think you have to take special steps  
with tmail to get direct delivery into that format. Without this, I  
think, the delivery mailbox will remain the aged mbox out in /var/ 
mail/spool and when the first IMAP or POP connection to the logical  
INBOX occurs the server processes "slurps" those messages into the  
IMAP MIX inbox store.

It sounds like this slurping is bogging things down. Someone else may  
jump in with further info but until then check the archives for how  
to get tmail to deliver directly to MIX.

HTH.
-Mike