From: nick@auger.net
To: "unicorn list" <mongrel-unicorn@rubyforge.org>
Subject: Re: A barrage of unexplained timeouts
Date: Tue, 20 Aug 2013 14:11:12 -0400 (EDT) [thread overview]
Message-ID: <1377022272.215912135@apps.rackspace.com> (raw)
In-Reply-To: <20130820174018.GA25675@dcvr.yhbt.net>
"Eric Wong" <normalperson@yhbt.net> said:
> 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.
I don't *think* so. Most requests finish <300ms. We do have some more intensive code-paths, but they're administrative and called much less frequently. Most of these pages complete in <3seconds.
For requests that made it to rails logging, the LAST processed request before the worker timed-out all completed very quickly (and no real pattern in terms of which page may be triggering it.)
> (enable $request_time in nginx access logs if you haven't already)
I'll enable this.
> 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).
TCP sockets, with nginx and unicorn running on the same box.
> With Unix sockets, I don't recall encountering recent problems under
> Linux. Which OS are you running?
Stock RHEL 5, kernel 2.6.18.
Thanks again,
-Nick
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next prev parent reply other threads:[~2013-08-20 18:11 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
2013-08-20 18:11 ` nick [this message]
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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