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The_Y's avatar
The_Y
Icon for Cirrus rankCirrus
Aug 08, 2016

Load balance based on a server CPU load

Hello all,

 

I am trying to find a mechanism to allow the F5 to pull CPU usage off one server in a pool of four. The end goal here is to send all traffic to one server using a higher priority group until that server reach the a certain CPU threshold (85%). That will trigger that node to be disable and send the rest of traffic to the other 3 servers in the pool.

 

I have research this a little bit and found a few options but I need to know if anyone has implement anything like this before and how effective one solution will be compared to the other? Or if any other solution is available to accomplish this?

 

  1. SNMP DCA monitor can be use to pull the CPU info but according to SOL 14127 it can be resource extensive
  2. Use an external monitor like the one on this link but I don't know how well this will work.

Thank you in advance for your answers.

 

application delivery
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4 Replies

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  • AJ_01_135899's avatar
    AJ_01_135899
    Icon for Cirrostratus rankCirrostratus
    Aug 08, 2016

    If this is a windows environment, you could use a WMI monitor.

     

    SOL 14127 mentions that it could be resource intensive if you log the monitor - so once you have it tuned properly, just turn off the logging and let the monitor run.

     

    • The_Y's avatar
      The_Y
      Icon for Cirrus rankCirrus
      Aug 09, 2016

      What's your take on the external monitor option?

       

    • Hamish's avatar
      Hamish
      Icon for Cirrocumulus rankCirrocumulus
      Aug 09, 2016

      External monitors are fine, but there's nothing to say they won't be as (Or more) resource intensive than the DCA option. Plus you have to maintain it.

       

      With regards to resource usage, DCA uses SNMP, which is built to be simple and light weight.

       

      The message about resource usage for SNMP in SOL 14127 is IF you have LOGGING enabled. Because the log file grows and there isn't an automatic mechanism to roll it over and/or clean it out.

       

      As AJ says above, just don't enable the logging, and go the SNMP route.

       

  • The_Y's avatar
    The_Y
    Icon for Cirrus rankCirrus
    Aug 09, 2016

    Thank you for your answers on this. I'm going to take a swing at the SNMP DCA monitor to see what I can get out of it.