Subject: qpopper and duplicate messages
From: Tom Bunger (tbunger@afhcan.org)
Date: Fri Apr 19 2002 - 09:59:21 AKDT
Hello all.
As an AKLUG lurker for the past few years, I have learned lots from you all
and am hoping someone has a few bits of wisdom related to the following
problem.
I am helping to troubleshoot a linux mail server. users on the LAN are
complaining about getting duplicate emails. This does not seem to occur
consistently, though. My research thus far has focused on the pop3
daemon. It was running qpopper 3.12. I downloaded source for the latest
ver (4.04) and compiled it (upgrading to the latest qpopper seemed to be
the solution of choice in the usenet threads i turned up on google). That
did not make the problem go away.
While troubleshooting this, I noticed a few things:
- lost of users seem to have their client software set to autocheck for
mail once every minute.
- when doing a "top" I saw a couple of popper processes grab as much as 60%
of the cpu for a short period of time
- df reports plenty of free space on all partitions
- this machine has been sailing along just fine for a few years under a
steadily increasing load
- nobody will admit to making any recent changes to the box or anything
else that might have caused this.
Server is a AMD k62-300, 64mb ram running redhat
5.2. qpopper4.04. sendmail 8.8.x. about 100-150 users (most are hitting
the machine across the LAN.).
So, I am thinking that:
- The machine is getting whacked really hard, causing the pop sessions to
get interrupted and then start over again, thus appending the user spool to
the temp file created by the interrupted process (I am not totally clear on
exactly how the files are dealt with by qpopper -- ie file locking, etc and
how it deals with an unexpected end of process like that.)
- The documentation for qpopper says that if a machine has a "great number
of users" then you may need to increase inetd timeout values but it doesn't
specify what a "great number" is nor does it specify suggested timeout values.
- qpopper runs through inetd with with the -s (server mode) command.
Anyone have any ideas or seen this before? Am I barking up the right tree?
Thanks in advance for your help.
/tom
---------
To unsubscribe, send email to <aklug-request@aklug.org>
with 'unsubscribe' in the message body.
This archive was generated by hypermail 2a23 : Fri Apr 19 2002 - 10:00:34 AKDT