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From: Eric Wong <normalperson@yhbt.net>
To: unicorn list <mongrel-unicorn@rubyforge.org>
Subject: Re: A barrage of unexplained timeouts
Date: Tue, 20 Aug 2013 17:40:18 +0000	[thread overview]
Message-ID: <20130820174018.GA25675@dcvr.yhbt.net> (raw)
In-Reply-To: <1377019663.33997248@apps.rackspace.com>

nick@auger.net wrote:
> "Eric Wong" <normalperson@yhbt.net> said:
> > Can you take a look at the nginx error and access logs?  From what
> > you're saying, there's a chance a request never even got to the Rails
> > layer.  However, nginx should be logging failed/long-running requests to
> > unicorn.
> 
> The nginx access logs show frequent 499 responses.  The error logs are filled with:
> 
> connect() failed (110: Connection timed out) while connecting to upstream
> upstream timed out (110: Connection timed out) while reading response header from upstream
> 
> What specific pieces of information should I be looking for in the logs?

Do you have any other requests in your logs which could be taking
a long time and hogging workers, but not high enough to trigger the
unicorn kill timeout.

(enable $request_time in nginx access logs if you haven't already)

Is this with Unix or TCP sockets?  If it's over a LAN, maybe there's
still a bad switch/port/cable somewhere (that happens often to me).

With Unix sockets, I don't recall encountering recent problems under
Linux.  Which OS are you running?

I hit several TCP bugs in the early 3.7 Linux kernels, too...
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  reply	other threads:[~2013-08-20 17:40 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-08-20 14:47 A barrage of unexplained timeouts nick
2013-08-20 16:37 ` Eric Wong
2013-08-20 17:27   ` nick
2013-08-20 17:40     ` Eric Wong [this message]
2013-08-20 18:11       ` nick
2013-08-20 18:49         ` Eric Wong
2013-08-20 20:03           ` nick
2013-08-20 20:42             ` Eric Wong
2013-08-20 21:19               ` nick
2013-08-20 21:32                 ` Eric Wong
2013-08-21 13:33                   ` nick
2013-08-22  2:32                     ` Jimmy Soho
2013-08-22  4:09                       ` Eric Wong
2013-08-22 13:10                         ` nick
2013-08-22 17:05                           ` Eric Wong

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