An express checkout? [was: Re: Postfix and Mailscanner sitting in a tree k-iss-ing]

[paddy]

On Fri, Dec 31, 2004 at 05:33:36PM +0000, Julian Field wrote:
> paddy wrote:
>
> >On Thu, Dec 30, 2004 at 06:00:20PM +0000, Julian Field wrote:
> >
> >
> >>Incidentally, something in the same vein has already been done for
> >>Communigate Pro, but I have never looked at that. I suspect (though
> >>without evidence either way) that it is not approx. 100% robust in the
> >>face of a concerted DoS attack. I go to some lengths to try to ensure
> >>that, when under attack, the MTA will give out long before MailScanner
> >>does.
> >>
> >>
> >
> >Looking at CriticalQueueSize I wonder if there might be some optimisation
> >possible that prefers to processes mail that is more likely to ham by some
> >simple criteria, a sort of express checkout.
> >
> >Possible devices to avoid starvation on the main queue could include
> >running
> >a slow queue along side the fast queue, so that the system is always
> >progressing,
> >and/or an elevator algorithm.
> >
> >
> Either you appear to have changed the subject without changing the
> Subject: or else I don't understand the link between the quoted text and
> your reply...

Okay, I confess it was a bit of a leap ... :)

I started from 'in the face of a concerted DoS attack'.

I've seen peaks of up to 500+ messages queued, which can take some time
(on a tiny, underpowered, overloaded system) to clear up.  At times like
that I find myself doing stuff like

tail -f maillog | grep delay | sed 's/\(...............\).*\]: \([^:]*\):.* delay=\([^,]*\),.*/\1 \2 \3/'

and trying not to worry about it!

(or maybe that should be xdelay, I don't know!)

But its not a feature request, more of a 'what do you think?'

So, yes, this no longer bears any relation to the previous Subject, sorry!

Regards,
Paddy
--
Perl 6 will give you the big knob. -- Larry Wall

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