4 Replies Latest reply on Mar 18, 2016 7:34 AM by Toby Erkson

    Do I need more RAM?

    Toby Erkson

      Tableau Server 9.2.4

      Windows 2008 R2

      8 cores (4 backgrounders, lots of extracts)

      64GB RAM

      90GB free disk space

       

      According to TabMon my Average % Committed Bytes In Use is 52%.  However, in my Windows Task Manager it's showing a consistent 91% - 92% physical usage, like, non-stop!  Which one do I use to determine if I need to add more memory?

        • 1. Re: Do I need more RAM?
          Jeff Strauss

          eek!  Somehow I trust windows task manager because it's more native, what does resource monitor show and the committed memory show within the processes tab.

           

           

          Why tabmon shows something different I don't know, but I plan on exploring this tool after my upgrade to 9.2.6 this w/e.

          • 2. Re: Do I need more RAM?
            Russell Christopher

            Heya Toby --

             

            Average % Committed Bytes In Use is different than the value Task Manager is showing you.

             

            From: Windows 7 memory usage: What's the best way to measure? | ZDNet (bold is mine):

             

            Committed Bytes has only the most casual relationship to actual usage of the physical memory in your PC. As Microsoft developer Brandon Paddock noted in his blog recently, the Committed Bytes counter represents:

            The total amount of virtual memory which Windows has promised could be backed by either physical memory or the page file.

            An important word there is “could.” Windows establishes a “commit limit” based on your available physical memory and page file size(s).  When a section of virtual memory is marked as “commit” – Windows counts it against that commit limit regardless of whether it’s actually being used.

            On a typical Windows 7 system, the amount of memory represented by the Committed Bytes counter is often well in excess of the actual installed RAM, but that shouldn't have an effect on performance. In

            This is exactly what you're seeing

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            • 3. Re: Do I need more RAM?
              Lindy Eberhart

              Thanks for those articles, Russel! Very helpful. I wanted to post my own thoughts on this as I was still a bit fuzzy after reading through everything. Please reply if I missed something.

               

              Key Takeaways:

              1. "Committed bytes" is generally not a useful way to measure actual physical memory usage.

              2. The best way (according to the ZDnet article) to measure physical memory usage is the "In Use" bar in Windows Resource Monitor:

              2016-03-18_10-28-19.png

              3. With that in mind, I believe the answer Toby's original question, is yes: you likely will want to increase the memory on your machine if that behavior is consistent.

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              • 4. Re: Do I need more RAM?
                Toby Erkson

                Thanks for the link Russell.  Important bits that I got from that page:

                Watching the color-coded Physical Memory bar graph on the Memory tab of Resource Monitor is by far the best way to see exactly what Windows 7 is up to at any given time.
                ...

                In Use (green) The memory shown here is in active use by the Windows kernel, by running processes, or by device drivers. This is the number that matters above all others. If you consistently find this green bar filling the entire length of the graph, you're trying to push your physical RAM beyond its capacity.

                and

                So why is watching Committed Bytes important? You want to make sure that the amount of committed bytes never exceeds the commit limit. If that happens regularly, you need either a bigger page file, more physical memory, or both.

                Thus knowing one's Commit Limit is necessary in conjunction with the Committed Bytes metric.  I probably should add that to TabMon.

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