On September 20, 2016 2:38:03 AM GMT+02:00, Grant <emailgr...@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.