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puzzling mysql load issue.

Discussion in 'General Discussion' started by noimad1, Mar 6, 2007.

  1. noimad1

    noimad1 Well-Known Member

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    Ok, I have a strange one for you guys.

    I have a customer who has a dedicated server with us. He only has two sites on the server, and they don't get that much traffic. One of the sites is fairly reliant upon mysql.

    However, his server load stays pretty high, and when I run "top" it shows mysql pretty steadily loading down the server. It can be anywhere from "30% cpu usage up to 95% cpu usage" pretty much non-stop.

    However, when I run "mytop" i barely see any mysql processes running. I mean, most of the time there are no proccess, and maybe every 10-15 seconds one will pop up there, then go away?

    So how can this be? Why would mysql be taking up so much load, when there aren't that many processes running?

    Am I missing something? I've done a /scripts/mysqlup --force and everything seemed fine. The other strange thing is that when this customer was on my shared server this problem didn't seem to exist?

    I mean the dedicated server is running slower then our shared server with 300+ users on it.
     
  2. bmcpanel

    bmcpanel Well-Known Member

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    I can't explain the way it all works, but I do know from experience that a single web site with heavy mysql usage can bring a server to its needs.

    Just recently, I had the same problem. I had a client who I knew had heavy mysql usage, but I was unable to pin him down as the reason for my high load average problem. I suspected, but was not sure he was the culprit. The load average was consistently above 3.00 and much higher at times.

    Finally, he left our service and as soon as he did, the server load average went back down to below 1.00. There is no doubt that his heavy mysql usage was causing the load average increase. Just one web site made this much difference.
     
  3. noimad1

    noimad1 Well-Known Member

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    Yea, I've seen that as well. However, my concern here is that when he was on our shared server, everything was fine. When I put him on a dedicated server it runs slow, with high load. And when I run mytop I'm seeing very few queries, even though regular top may show mysql at 90% cpu usage?
     
  4. nickp666

    nickp666 Well-Known Member

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    which os, and what kernel version is it running?

    I had a similar scenario a few months back, turned out to be a buggy RH kernel, a quick upgrade fixed it
     
  5. katmai

    katmai Well-Known Member

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    this may be happening because of long mysql queries.

    the mysql database needs to be analyzed, and after that some optimizations may be done.

    regards
     
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