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On September 20, 2016 2:38:03 AM GMT+02:00, Grant <emailgrant@×××××.com> wrote: |
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>>>> My web server's response time for http requests skyrockets every |
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>>>> weekday between about 9am and 5pm. I've gone over my munin graphs |
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>and |
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>>>> the only one that really correlates well with the slowdown is "TCP |
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>>>> Queuing". It looks like I normally have about 400 packets per |
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>second |
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>>>> graphed as "direct copy from queue" in munin throughout the day, |
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>but 2 |
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>>>> to 3.5 times that many are periodically graphed during work hours. |
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>I |
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>>>> don't see the same pattern at all from the graph of all traffic on |
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>my |
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>>>> network interface which actually peaks over the weekend. TCP |
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>Queuing |
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>>>> doesn't rise above 400 packets per second all weekend. This is |
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>>>> consistent week after week. |
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>>>> |
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>>>> My two employees come into work during the hours in question, and |
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>they |
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>>>> certainly make frequent requests of the web server while at work, |
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>but |
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>>>> if their volume of requests were the cause of the problem then that |
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>>>> would be reflected in the graph of web server requests but it is |
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>not. |
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>>>> I do run a small MTU on the systems at work due to the config of |
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>the |
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>>>> modem/router we have there. |
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>>>> |
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>>>> Is this a recognizable problem to anyone? |
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>>> |
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>>> |
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>>> I'm in the midst of this. Are there certain attacks I should check |
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>for? |
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>> |
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>> |
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>> It looks like the TCP Queuing spike itself was due to imapproxy which |
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>> I've now disabled. I'll post more info as I gather it. |
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> |
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> |
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>imapproxy was clearly affecting the TCP Queuing graph in munin but I |
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>still ended up with a massive TCP Queuing spike today and |
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>corresponding http response time issues long after I disabled |
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>imapproxy. Graph attached. I'm puzzled. |
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> |
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>- Grant |
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|
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Things to check for: |
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Torrent or other distributed downloads. |
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Download program with multiple download threads |
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|
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Maybe another proxy running? Esp. as you saw this also with imapproxy. |
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|
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-- |
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Joost |
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-- |
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Sent from my Android device with K-9 Mail. Please excuse my brevity. |
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