From: "J. Roeleveld" <joost@antarean.org>
To: gentoo-user@lists.gentoo.org
Subject: Re: [gentoo-user] Re: TCP Queuing problem
Date: Tue, 20 Sep 2016 13:50:10 +0000 [thread overview]
Message-ID: <501ED693-3FD7-4C58-B76D-3A811C948DFF@antarean.org> (raw)
In-Reply-To: <CAN0CFw1KXZgx_PFDHhw9PsHADtQTOwcJawddOc9NtNsY3qDbCw@mail.gmail.com>
On September 20, 2016 2:38:03 AM GMT+02:00, Grant <emailgrant@gmail.com> wrote:
>>>> My web server's response time for http requests skyrockets every
>>>> weekday between about 9am and 5pm. I've gone over my munin graphs
>and
>>>> the only one that really correlates well with the slowdown is "TCP
>>>> Queuing". It looks like I normally have about 400 packets per
>second
>>>> graphed as "direct copy from queue" in munin throughout the day,
>but 2
>>>> to 3.5 times that many are periodically graphed during work hours.
>I
>>>> don't see the same pattern at all from the graph of all traffic on
>my
>>>> network interface which actually peaks over the weekend. TCP
>Queuing
>>>> doesn't rise above 400 packets per second all weekend. This is
>>>> consistent week after week.
>>>>
>>>> My two employees come into work during the hours in question, and
>they
>>>> certainly make frequent requests of the web server while at work,
>but
>>>> if their volume of requests were the cause of the problem then that
>>>> would be reflected in the graph of web server requests but it is
>not.
>>>> I do run a small MTU on the systems at work due to the config of
>the
>>>> modem/router we have there.
>>>>
>>>> Is this a recognizable problem to anyone?
>>>
>>>
>>> I'm in the midst of this. Are there certain attacks I should check
>for?
>>
>>
>> It looks like the TCP Queuing spike itself was due to imapproxy which
>> I've now disabled. I'll post more info as I gather it.
>
>
>imapproxy was clearly affecting the TCP Queuing graph in munin but I
>still ended up with a massive TCP Queuing spike today and
>corresponding http response time issues long after I disabled
>imapproxy. Graph attached. I'm puzzled.
>
>- Grant
Things to check for:
Torrent or other distributed downloads.
Download program with multiple download threads
Maybe another proxy running? Esp. as you saw this also with imapproxy.
--
Joost
--
Sent from my Android device with K-9 Mail. Please excuse my brevity.
next prev parent reply other threads:[~2016-09-20 13:50 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-17 21:13 [gentoo-user] TCP Queuing problem Grant
2016-09-19 17:23 ` [gentoo-user] " Grant
2016-09-19 21:25 ` Grant
2016-09-20 0:38 ` Grant
2016-09-20 13:08 ` Grant
2016-09-21 4:01 ` Kai Krakow
2016-09-21 14:30 ` Grant
2016-09-21 19:29 ` Kai Krakow
2016-09-21 19:37 ` Grant
2016-09-21 20:06 ` Kai Krakow
2016-09-21 20:28 ` Kai Krakow
2016-09-21 19:41 ` Kai Krakow
2016-09-21 19:53 ` Grant
2016-09-21 20:18 ` Kai Krakow
2016-09-21 20:47 ` Grant
2016-09-21 21:44 ` Michael Mol
2016-09-22 0:30 ` Grant
2016-09-22 7:06 ` Kai Krakow
2016-09-25 0:25 ` Grant
2016-10-01 9:57 ` Grant
2016-09-20 13:50 ` J. Roeleveld [this message]
2016-09-20 14:53 ` Grant
2016-09-20 18:06 ` J. Roeleveld
2016-09-20 19:52 ` Grant
2016-09-20 20:19 ` Alarig Le Lay
2016-09-22 16:58 ` Volker Armin Hemmann
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