Forum Discussion

Michel_van_der_'s avatar
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Nov 14, 2003

CPU utilization and kernel memory utilization

Can I get my hands on those using iControl? This is for a BigIP running


4.2 at the moment. Hope to go to 4.5 RSN.



The information in ITCMLocalLB.Global.get_statistics




quite the later.




3 Replies

  • What specifically are you looking to infer from the CPU and kernel memory utilization? The mem pool total and used metrics relate to the amount of memory the core processing subsystem allocates and uses from the system. To a point you can infer red-lining from these metrics as they directly relate to the amount of configuration and connection information the processing components have free. When the used metric reaches the total then that would imply the box is reaching capacity.



    In 4.2, as far as my memory serves me, these are the only 2 memory metrics available.



  • I'm mostly interested in this data for capacity planning purposes. When


    should I start thinking about adding memory, should I perhaps move


    some load balancing service from one set to another, those types of





    The issue that brought this to my attention was that I noticed one of


    our F5 boxes rebooted spontaneously the other day. Turns out it was


    because the kernel memory consumption reached 95%. However the


    data from the statistics I got through iControl showed only about 75%


    utilization (which is what 'bigpipe ms' showed me as well).



    Looking through your various tech articles (e.g. SOL192), it is not clear


    to me, how the output from 'bigpipe ms' (and in extension the data


    gathered from iControl), relates to the kernel message we were seeing,


    i.e. there seems to be a significant discrepency.



    Also, it would be nice to have a more extensive description of all of the


    statistics that are available.



    Also, what about CPU utilization? Is that available though iControl? My


    boxes don't appear even slightly stressed, but I'd like to track it to make





    Thanks, Michel
  • I like to refer to this issue as "red-lining". For the next generation of products we are working on building more of these types of features into the product. I don't have the information when these features will be available but suffice it to say it will be fairly soon as this is not a uncommon reuqest. On the 4.x platforms there were platform architectural limitations stopping us from accurately determining red-line situations.



    As for CPU metrics, this is something we are also adding in future versions but is not available on 4.2.



    I try to answer as many product related questions as possible here but when it goes too far beyond the development of iControl applications you will get better support and more reliable answers by contacting F5 technical support directly. Their specialty is with questions like this.



    F5 Technical Support




    Phone: 206-272-6888