HTTP downloads randomly get stuck until client timeout

[Richard Stanway]

That ticket does look like the same issue I'm having as I was indeed using
timer_resolution. The problem seems to have coincided with a recent Debian
kernel update, so it's possible they backported those changes. I have
removed timer_resolution from my config and so far have been unable to
reproduce the issue.

Thanks for the quick reply!

Regards,
Richard.


On Tue, Jan 31, 2017 at 4:32 PM, Maxim Dounin <mdounin at mdounin.ru> wrote:

> Hello!
>
> On Tue, Jan 31, 2017 at 04:19:59PM +0100, Richard Stanway wrote:
>
> > Hi all,
> > I'm experiencing odd behavior with some larger HTTP file downloads from
> my
> > site. The files will download for a seemingly random amount of bytes then
> > the connection freezes until "send_timeout" expires, at which point the
> > error log shows "client timed out (110: Connection timed out) while
> sending
> > response to client".
> >
> > A tcpdump shows both ends successfully passing packets with no packet
> loss.
> > nginx is pretty stock from the nginx.org repository, no 3rd party
> modules
> > or complex options, mostly static files and fastcgi / PHP. The behavior
> is
> > very intermittent, but happens regardless of client browser / IP /
> > requested file.
> >
> > I was able to captured a debug log when this happened, it is available at
> > https://hastebin.com/tevusuhobe.m (some rewrite details and variables
> have
> > been omitted)
>
> [...]
>
> > sendfile, tcp_nopush, tcp_nodelay are enabled.
> > accept_mutex, aio is disabled.
> >
> > Linux karak 3.16.0-4-amd64 #1 SMP Debian 3.16.36-1+deb8u2 (2016-10-19)
> > x86_64 GNU/Linux
> >
> > I've also tried mainline nginx/1.11.9 from the nginx.org repository and
> the
> > problem persisted. Any advice on what I should be looking at to resolve
> > this would be very welcome!
>
> This sounds similar to https://trac.nginx.org/nginx/ticket/1174
> (though the kernel looks old enough, but there may by backports).
> Are you using timer_resolution?
>
> --
> Maxim Dounin
> http://nginx.org/
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>
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