I was having hell with my CentOS4.2/BQ box and qpopper. In
/etc/xinetd.d/pop3 I changed the server_args to say:
server_args = in.qpopper -S -R
-R = Disables reverse lookups on client IP addresses.
-S = Enables server mode. This mode reduces disk I/O and disk space usage
when popper is used on a system that serves
POP only users exclusively.
Today the server has run without any issues at all. So it appears to have
fixed the problem for now. However, I'd still like to look into using
Dovecot as an alternative. Maybe I'll get around to testing it sometime
soon.
----- Original Message -----
From: "Rusty Waybrant" <rwaybrant (at mark) gramtel.net>
To: <coba-e (at mark) bluequartz.org>
Sent: Tuesday, March 07, 2006 2:46 PM
Subject: [coba-e:04261] fyi: Re: Optimizing qpopper or POP3 alternative
>I have a BQ server that seems to be affected by this POP3 issue as well.
>
> After upgrading from FC1/BQ to CentOS4.2/BQ, the POP3 issue remains. From
> the client-side of POP3, it seems to hang on authentication, specifically:
> "pass ****", and occasionally getting the EOF or I/O error. Once this
> starts, every new attempt for POP3 just builds up until there is 80-120
> POP3 sessions ESTABLISHED (netstat). There are a few "-ERR POP EOF or I/O
> Error" in the logs during the time of high usage, but for the most part,
> this is just timeout errors on the client-side.
>
> On the old server, it required the updated pwdb RPM and needed to run a
> db_recover, and then kill off all the current POP3 sessions to resolve the
> issue... I searched around and this looks like this is replaced by
> "/etc/rc.d/init.d/dbrecover start", if it is truly related to the password
> database. However, I never ran this as it appeared to eventually clear
> itself up the two times POP3 flaked-out on the new (two-day old) platform,
> but not before the POP3 issue was widely noticed.
>
> If xinetd is the issue, which I remember plenty of problems related to
> inet on heavily used Cobalts, shouldn't the Hosting edition use qpopper in
> standalone mode instead of xinetd? Or at least be compiled to be easily
> switched? I don't have gcc on the server, so this is not that simple. The
> default of xinetd.conf was maybe not best for a busy mail server,
> instances was 60 and cps was 25 30, and changed to UNLIMITED and 50 10,
> and will change instances to a more sane setting later.
>
> If qpopper is the issue and Dovecot is going to be eventually replaced, is
> this the RPM in the CentOS 4 base? Is there anything special needed to get
> this Dovecot RPM to work with the 'virtual' users and pwdb? Or is source
> and gcc needed? CentOS 4 has Dovecot or Cyrus-imapd, replacing the UW
> imapd from CentOS 3. I have no opinion on either of the options available
> in CentOS 4, except that Cyrus looks like it prefers virtual users (MySQL)
> instead of regular Linux users, so it might be easier to hook to pwdb.
>
> Finally, is pwdb optimized to work in high workload environments? I ask
> this because the previous platform had issues with POP3, and 9 times out
> of 10 I was running something to clean-up and repair the user database to
> fix the issue and not so much tweaking xinetd/pop3 settings... It is
> almost the same problem now, except the new platform appears to be able to
> recover by itself, well, eventually.
>
> The server (old and new) is 2.8GHz, 2GB (1GB for old server), 2 x 80GB
> SATA, and load has always been lower than 1.00. There are 800+ users,
> mainly business users so heaviest usage is 8AM-5PM, and I can see 50-80
> users per minute (and no, these are not all the same users every minute).
>
>
>
> Rusty
>
> -----Original Message-----
> From: patricko [mailto:patricko (at mark) staff.singnet.com.sg]
> Sent: Monday, March 06, 2006 10:02 PM
> To: coba-e (at mark) bluequartz.org
> Subject: [coba-e:04258] fyi: Re: Optimizing qpopper or POP3 alternative
>
> Hi,
>
>
> Qpopper still Can Work with 1500++ users.
>
> But you need to Remove Xinetd configuration from qpopper.
>
> Basically, xinetd temporary stop connection after Threshold is reached.
>
>
> Steps involved:
>
> 1) Recompile Qpopper without Xinetd
> 2) Run with -s -R -S
>
>
>
> Cheers
> patrick
>
>
>
>
> On Mon, 6 Mar 2006 11:08:46 -0600
> "Chris McGinnis" <chrism (at mark) t3wireless.com> wrote:
>
>> What version of Dovecot did you install and how did you install it?
>> The qpopper thing is getting way out of hand on a production server
>> and I need to get it resolved ASAP.
>>
>>
>> ----- Original Message -----
>> From: ""Ing. Ernesto PñÓez Estñ×ez"" <info (at mark) ecualinux.com>
>> To: <coba-e (at mark) bluequartz.org>
>> Sent: Friday, March 03, 2006 1:01 PM
>> Subject: [coba-e:04248] Re: Optimizing qpopper or POP3 alternative
>>
>>
>> > -----BEGIN PGP SIGNED MESSAGE-----
>> > Hash: SHA1
>> >
>> > I installed dovecot and was able to get rid of this problem. qpopper
>> > was a bit slow... and dovecot solved that situation.
>> >
>> > epe
>> >
>> > Chris McGinnis wrote:
>> >> I have setup a machine with NuOnce CentOS + Bluequartz. I have
>> >> migrated 100 virtual sites from a RaQ 550 and have run into problems
>> >> with qpopper.
>> >>
>> >> After a while there will be 50+ qpopper instances running and
>> >> client connections will timeout saying:
>> >> -ERR POP EOF or I/O Error
>> >>
>> >> Any recommendations on optimizing qpopper or possibly replacing
>> >> qpopper with something else? All of these sites came from a
>> >> RaQ550, I would expect my new server to handle the load just fine.
>> >>
>> >> The specs on the machine are: 3.2Ghz, 2GB ram, SATA 200GB HDD
>> >>
>> >> -Chris
>> >>
>> >>
>> >>
>> >
>> > - --
>> > Ing. Ernesto PñÓez Estñ×ez
>> > http://www.ecualinux.com
>> > USA: + 1 404 795 0321
>> > Ecuador: (02)3412402 - (09) 9246504
>> > -----BEGIN PGP SIGNATURE-----
>> > Version: GnuPG v1.2.6 (GNU/Linux)
>> > Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org
>> >
>> > iD8DBQFECJJ68sSWs7RP4EMRAklmAKCPyAYygp/fvhM/f1PjPfSHslASPQCg8Ee2
>> > 2JSUL8a9P8zJHQh8lspYk+4=
>> > =AyJ/
>> > -----END PGP SIGNATURE-----
>> >
>> >
>>
>>
>
>
> --
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