Phil Pennock wrote:
> On 2009-02-22 at 20:23 -0800, Marc Perkel wrote:
>
>> Just wondering about the 4096 connection barrier. With the size of
>> servers these days it's easy to build a box that can handle 4096
>> connections at once. Any chance of eliminating it in the next release?
>>
>
> More than 4096 connections, all actually doing work? Sounds more like
> you're discovering the down-side to tar-pitting within Exim, instead of
> in a small daemon dedicated to tar-pitting.
>
> src/daemon.c, the limit is a sanity-check on smtp_accept_max; as far as
> I can see from skimming the source, this isn't used to keep any
> collections within the size of another data structure, such as might be
> passed to select().
>
> So you should be safe to just increase the maximum check.
>
> Note though that some other stuff scans linearly through smtp_slots
> assuming that this is a fairly lightweight approach. If you're raising
> this to a much higher figure, Exim might spend more and more time
> scanning smtp_slots for every connection -- just keep an eye on the CPU
> usage of the main daemon and, if it gets out of hand, you've raised the
> limit too far. You might then consider submitting a patch to change the
> relevant logic to something which scales better.
>
>
>> And - is there going to be a 4.70 version? What's new and exciting in
>> development?
>>
>
> Yes.
>
> ChangeLog:
> http://vcs.exim.org/viewvc/exim/exim-doc/doc-txt/ChangeLog?view=markup
> NewStuff:
> http://vcs.exim.org/viewvc/exim/exim-doc/doc-txt/NewStuff?view=markup
>
> Regards,
> -Phil
>
>
Well, I'm not up to 4096 yet but often run 900 on Monday mornings. I'm
filtering spam for over 4000 domains and this is the main box. I might
have a project coming up processing far more volume that now.
This box is fast. I'm offloading spamassassin on several other servers.
I'm using a ram disk for the email queue. I might be adding another
12,000 domains. I'm not doing a lot of delays, although I do throw in a
few seconds of suspicious connections but no more than 10 seconds total.
So although 4096 sounds like a lot if you throw enough email volume on
it you can get there.
