Re: [cobalt-users] RaQ4 - CPU overload

[ajongsma <andries.jongsma@xxxxxxxxxxx>]

This is becoming a nice and long thread by now but I'm learning a lot. Thnx
guys :D

I have changed a "minor" thing on which I stumbled going through some .cf's.

  # You can force Majordomo to delay any processing if the system load is
too
  # high by uncommenting the following lines.  THIS ONLY WORKS if your
"uptime"
  # command (usually found in /usr/bin/uptime or /usr/bsd/uptime)
  # returns a string like:
  #   5:23pm  up  5:51,  9 users,  load average: 0.19, 0.25, 0.33
  #
  $max_loadavg = 19;                 # Choose the maximum allowed load
Yes, I changed the $max_loadavg = 5; to $max_loadavg = 19; The CPU is now
jumping up and down with the CPU load but the average is now 4.38 instead of
12. The "feature" rejecting connections is also far lower in number then
before. I know this is only a snapshot of a certain moment so I will have to
see for a few more days but it looks promising :D

By now I know what qpopper does and that it has a very high load. I also
know that qpopper is started from inetd.
I have playd around with the /usr/sbin/ipop3d but when activated there is a
major problem with authentication. Changed it back to the original qpopper
so I still have the problem with the load caused by the qpopper.
1.) I saw that qpopper has the same load with an empty mailbox. Could this
load have something to do with the locking?
2.) Imap has been disabled so the only thing left is SMTP and POP3. If this
is the "guarantee" you're talking about I think I can. Could you please
confirm my thought is right and if possible give me any direction on how to
get/find a variation on qpopper or a qpopper itself which be run as a
"server mode" instead from inetd?


Grtz,

Andries

Graeme Fowler wrote:

> ajongsma wrote:
> > Why are there qpoppers from root? This mostly seems to happen when
> inetd is
> > restarted but that isn't the case and why do they take that much CPU
> (he
> > record I have seen is one qpopper with 86% CPU)?
>
> qpopper starts from inetd, which runs as root. It first spawns a process
> owned by root which reads in and copies the entire mailbox to another
> file, then changes user ID to become the ID of the user who wants the
> email. It is this mailbox read/copy which creates the load initially.
>
> In a previous job, we used a very hacked-about version of qpopper which
> ran in 'server mode' - it doesn't copy the mailbox and operates directly
> on it. This can be A Bad Thing, unless you can guarantee that the only
> mail access is via POP.
>
> I'll reiterate what I said earlier: Don't leave mail on server. POP3 is
> not really designed for it.
>
> Graeme
>
> _______________________________________________
> cobalt-users mailing list
> cobalt-users@xxxxxxxxxxxxxxx
> To Subscribe or Unsubscribe, please go to:
> http://list.cobalt.com/mailman/listinfo/cobalt-users