On Mon, 2011-07-11 at 13:47 -0500, Stan Hoeppner wrote:
On 7/11/2011 11:22 AM, lists@truthisfreedom.org.uk wrote:
They're showing as between 20 and 24 for the POP3 servers and 1.4 for the IMAP servers.
FULL STOP. Oh my lordy. Something is ridiculously wrong here. You have 12 physical cores with only ~600 simultaneous pop connections. That's only 50 per core. Even if those are the 'lowly' 2.4GHz 5645 chips each core should be able to handle a couple hundred pop connections. If you were truly hitting an actual load of 20-24, a single one of those boxes would be bringing your NetApp to its knees (assuming GbE) due to the amount of IO that would be taking place with the CPUs this busy.
Good, so my assumption that something was wrong was correct and as the NetApp isn't on its knees...
So a kernel update is more than sensible...
Disable HT regardless of kernel upgrading. See if it helps the load issue with the current kernel. Then go ahead and upgrade the kernel. If the CentOS repos don't have anything in the 2.6.3x series grab: http://www.kernel.org/pub/linux/kernel/v2.6/linux-2.6.39.3.tar.bz2
and roll your own. Though I'd guess since you're a CentOS user you probably don't have any experience rolling kernels.
LOL. I'm not a fan of Centos but it's what we've got to play with here - We'll be running Debian (or possibly even Gentoo if I have my way...) on the next load of servers and custom kernels aren't an issue.
/me misses stage one gentoo installs... :(
Now, considering you're running a many years old version of Dovecot, which is no longer officially supported, you really need to upgrade. Safe bet is to grab the latest 1.2.x RPM you can get.
We've built our own RPMS for 1.2 - we're upgrading these servers tomorrow... :)
Kind regards,
Matt