Server Lag Issue Investigation

Discussion in 'Site & Server Administration' started by twalters84, Oct 19, 2008.

  1. #1
    Greetings,

    As you all may know, I have been working the last couple weeks to try to figure out what is causing the lag issue.

    I thought I made a breakthrough when I came across this article:

    http://www.bennadel.com/blog/154-ColdFusion-Session-Management-Revisited-User-vs-Spider-III.htm

    Basically, when users come to the websites, session variables are created to store common elements such as host name and geo data. Session (cookie data) is stored in two places - on users personal computers and on the server. The problem started occurring because cookies are disabled in web crawlers. So each time a web crawler was crawling a webpage, the server would attempt to initiate new session variables. Over a couple hours,
    the memory and CPU usage would increase dramatically.

    So the solution to this problem was to differentiate web crawlers from regular users. I updated the code on all websites in the application.cfm file. When a web crawler is detected, I disabled session management. When a regular user is detected, I enabled session management. Thus, session information is only created for regular users now.

    We also put an additional 1 GB of RAM on the server.

    The lags seems to have disappeared, but with closer investigation, it still looks like memory increases over time. I will explain more momentarily...

    Sincerely,
    Travis Walters
     
    twalters84, Oct 19, 2008 IP
  2. twalters84

    twalters84 Peon

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    #2
    Hello again,

    I recently installed fusionReactor on the server.

    Here is a graph of the CPU usage over time:

    http://www.lukebouman.com/temp/server_cpu.bmp

    Here is a graph of the Memory Usage over time:

    http://www.lukebouman.com/temp/server_memory.bmp

    The CPU usage seems to have a pattern to it. It shoots up the same amount about every hour and a half.

    With the memory graph, the blue area is used memory. It increases over time and drops off. However, when it increases it also increases the allocated memory and the allocated memory never decreases unless I restart coldfusion.

    Does anybody have an ideas why this could be?

    Sincerely,
    Travis Walters
     
    twalters84, Oct 19, 2008 IP
  3. bucasia

    bucasia Peon

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    #3
    Is this a linux or windows server? (apologies if I missed that in the post)

    You really need to find out what process is using the cpu. I'm guessing it's a dual core cpu as, when the cpu usage max's out at 50%, I think you'll find it's one process maxing out a core.

    The graph is very regular so it's probably some cron job or something running
     
    bucasia, Oct 20, 2008 IP