high Traffic setup problem, module status don't deliver data

[Maxim Dounin]

Hello!

On Tue, Feb 11, 2014 at 01:10:59PM +0100, Aleksandar Lazic wrote:

> 
> Am 11-02-2014 12:48, schrieb Maxim Dounin:
> >Hello!
> >
> >On Tue, Feb 11, 2014 at 12:34:59PM +0100, Aleksandar Lazic wrote:
> >
> 
> [snipp]
> 
> >>>You haven't shown your server level configuration.
> >>>Do you use deferred accept?
> >>
> >>yes
> >>
> >>listen       <IP>:80 deferred default_server;
> >
> >Try switching it off, there could be a problem if kernel decides
> >to switch to syncookies, see this ticket for details:
> >
> >http://trac.nginx.org/nginx/ticket/353
> >
> >(The problem is fixed in 1.5.10, and 1.4.5 will have the fix,
> >too.)
> 
> Ok thanks.
> I have now removed deferred  and added backlog=1024

Does it actually solve the problem?  It also would be intresting 
to know what exactly did it - removing deferred or adding backlog?

(As for backlog size, I usually set it to something big enough to 
accomodate about 1 or 2 seconds of expected peek connection rate.  
That is, 1024 is good enough for about 500 connections per second.  
But with deferred on Linux, it looks like deferred connection are 
sitting in the same queue as normal ones, and this may drastically 
change things.)

> Should I add deferred again when I update to 1.4.5?

It should be safe, though I don't recommend it unless it's 
beneficial in your setup.

-- 
Maxim Dounin
http://nginx.org/