So this is a step in the right direction. But still far less than optimal. The read/write lock contention on mbox is unnecessarily eating up system resources (mainly memory), and causing unnecessary delivery delays to the mailbox. You should really start looking at migrating to maildir. It's not that difficult (though maybe more so with 1.0.7) if you don't have a ton of mailboxes, and especially with POP since the mailboxes typically wont be holding much mail to migrate. How many do you have?
There's around four hundred mail boxes or so. Some used more intensively than others.
Our server is with Rackspace, and RHEL5 is the OS they offered us as an upgrade path from RHEL4. So they're getting the support from Red Hat and we're getting the support from Rackspace.
The plot thickens again. You're using a rented server. Sigh...
This entire thread could have been greatly shortened, saving all of us much time, if you'd have given all these details up front.
Is this a cloud server (shared host), or a dedicated server?
It's a dedicated server
FWIW, you don't have RHEL5, but CentOS 5. Hosting companies don't pay for RHEL licenses for 10s of thousands of hosts.
It's RHEL5:
$cat /etc/issue Red Hat Enterprise Linux Server release 5.8 (Tikanga)
The cost of the license is included in our contract.
I have a few salient recommendations for you:
- Migrate to maildir. It is far more appropriate for a POP workload.
Yes, this will be our next course of action
- Switch to a hosting provider that offers much more recent software.
We can upgrade the software if we wish, but will no longer get full support from Rackspace if we do this.
- Or, get a colo server so you can use whatever software you wish.
We can install whatever software we wish at the moment, but see the point above.
Finally, if this email service you're providing isn't all that critical to you or your organization, simply prod along as you have been, fighting these problems frequently along the way.
It's kind of working ok now but we will go with your recommendation of switching to maildir when we have time. Thanks for your help