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hi all, can some one explain to me what the difference between CPU load and server load is? and what is load1, load5, load15 etc. my cpu load stays fine ...
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  1. #1
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    server load vs cpu uage


    hi all,

    can some one explain to me what the difference between CPU load and server load is? and what is load1, load5, load15 etc.

    my cpu load stays fine but server load goes over the red line a fair bit. Should i be worried? I have 1 site on nthe server only and I haven't noticed any slow down in loading or other issues due to excessive server load.

    cpu-1.jpg
    load-1.jpg
    server1.jpg

  2. #2
    Penguin of trust elija's Avatar
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    Load average shows how effectively the processor is being used. As your red line is at 4, I assume you have a quad core? In such a case, if your load average was consistently 4.00, your processor would be fully used with no threads hanging around waiting. Less than 4.00 would show spare capacity and consistently more than 4.00 would indicate the processor is over-used.

    In your case, as far as I can see, you have spare capacity on your processor with the occasional spike. I would be asking myself what was going on at those times; is the site busier, is there a backup or some other intensive process, could there be some inefficient queries accessing badly indexed database tables? That last one often shows that behaviour at a sites busier times.

    http://www.linuxjournal.com/article/9001
    "I used to be with it, then they changed what it was.
    Now what was it isn't it, and what is it is weird and scary to me.
    It'll happen to you too."

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    Quote Originally Posted by elija View Post
    As your red line is at 4, I assume you have a quad core?
    ------------
    yes this one is a quadcore server
    ------------

    could there be some inefficient queries accessing badly indexed database tables? That last one often shows that behaviour at a sites busier times.
    ------------
    how would I go about investigating this further? I have phpmyadmin and I did recently optimize all tables.

    thanks

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    Penguin of trust elija's Avatar
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    You can identify slow queries using the slow query log and then use explain to find out what is going on.

    Another excellent read for you.
    "I used to be with it, then they changed what it was.
    Now what was it isn't it, and what is it is weird and scary to me.
    It'll happen to you too."

    Grandpa Simpson



    The Fifth Continent

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    thanks for the links.. I have a single oscommerce site on this server and I believe the main culprit causing the high load spikes will be mysql

    this command is almost always running ( /usr/libexec/mysqld --basedir=/usr --datadir=/var/lib/mysql --user=mysql --pid-f ... )
    and CPU usage is almost always above 40/ 50% for this command.

    I will dig a bit deeper into it but I have a feeling I will need to hire a coder to optimize the mysql queries

  7. #6
    Penguin of trust elija's Avatar
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    The good thing here is that this is not an emergency but if you are the decision maker here, it is definitely worth checking out before it is. I speak from bitter experience when I say troubleshooting something like this is no fun when the site is virtually down!
    "I used to be with it, then they changed what it was.
    Now what was it isn't it, and what is it is weird and scary to me.
    It'll happen to you too."

    Grandpa Simpson



    The Fifth Continent

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