[ILUG] extremely slow pop3, but imap is fine

[Justin Mason]

On Fri, Mar 27, 2009 at 10:00, Kae Verens <kae at verens.com> wrote:
> Kae Verens wrote:
>>
>> Kenn Humborg wrote:
>>  >> On Thu, Mar 26, 2009 at 5:04 PM, Kae Verens <kae at verens.com> wrote:
>>  >>> all was running perfectly for months until today.
>>  >> Any patches applied? Anything showing on the logs? Tried to restart
>>  >> services/box ?
>>  >
>>  > Run strace -p <PID> on the server process.  It might provide
>>  > clues as to what's going on during the delays.
>
> turns out that another guy in our datacentre is having the same problem, so
> this may be a router problem.
>
> any ideas why it would mostly affect POP3? appears to be slowing our other
> services, but POP3 is the most serious.

this looks to me like the kernel buffers are filling up, returning the
EAGAIN ("try again later" basically) to the app level.  have you
considered it may be a broken QoS policy or similar on the router
deprioritising POP3 traffic?

--j.