Re: [exim] 4096 connection barrier

Ted Cooper wrote:
> Marc Perkel wrote:
>
>> 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.
>>
>
> The 4096 limit might be more aimed at the limits imposed by linux
> itself. There are open file descriptor limits (default limits are 1024
> per process) which you may reach. I suspect there would be some others
> too, but they are all trivial to increase. It's just a matter of
> adjusting them all which is why this would be considered a local tuning
> customisation and not something that would enter the distribution code base.
>
> I know you already use multiple MX records, have you considered
> splitting the MX onto different machines so that you have a fail over?
> Or use round robin DNS to split the traffic between multiple machines?
>
>

I could virtualize several incidents of Exim to get around it (OpenVZ)
but I'm just saying basically if this is an easy fix it might be worth
looking at.