1 Reply Latest reply on Jun 26, 2018 9:19 PM by afaulkner

    Values no longer compressed after restarting OPC interface

    FLeonard

      The PI Server is using archive files at a rate 5 to 7 times faster than usual: archive Lifetime has dropped down, and Add Rate has increased. Here is what I can say so far:

       

      • Values no longer compressed after restarting OPC interface
      • Difference between timestamps of 2 consecutive data points is equal to advise scan rate
      • Difference between values of 2 consecutive data points is smaller than CompDev
      • Problem started within a minute of restarting the interface
      • Compression ratio is down to 4-5 % (was 75 % before incident)
      • 2 instances of PI-OPC interface running on node. Only one is affected
      • Interface configuration was not changed. Its BAT file dates back to 2011
      • Tags appeared configured correctly
      • No tag was edited the day the problem started

       

      I am stumped, and looking for ideas to fix the problem. Thank you all.

       

      François

        • Re: Values no longer compressed after restarting OPC interface
          afaulkner

          This type of behavior often occurs if a tag that was buffered starts bypassing the buffer (usually due to a configuration issue with the PI Buffer Subsystem).

           

          If you expect this tag to be buffered, let's get a sense of the health of the buffer by running these two commands:

          • pibufss -cfg
          • pibufss -trace <Point ID of an Interface Tag>

           

          If the tag is currently being buffered, we will want to determine if the buffer subsystem has cached the correct compression settings by running the following command for the same tag as above:

          • pibufss -sd <Point ID of an Interface Tag>

           

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