6 Replies Latest reply on Jul 19, 2018 7:57 AM by gabriela..zorrilla

    Running with no swap?

    gabriela..zorrilla

      I hate using swap. We have a 32gb server, what happens with Tableau on linux if runs out of ram and has no swap to rely on?

        • 1. Re: Running with no swap?
          Jeff Strauss

          Not sure.  I'm guessing that process crashing will start to occur.  I advise to make sure you have enough memory.  The recommended amount is 8 gig per core.

          • 2. Re: Running with no swap?
            gabriela..zorrilla

            Hi Jeff, thanks. 8gb per core of swap you say? classic Tableau. Want more safety, more performance? Sure, just add more cores, more ram and in this case, more swap! Optimizing the app? Why bother?

             

            Haha.

             

            Again, thanks.

            • 3. Re: Running with no swap?
              Jeff Strauss

              (RAM MEMORY) The recommended RAM is 8 gig per core.  If you have this amount, then hopefully swap shouldn't be needed.  I'm not sure on your tone, but I can tell you that if you try and fill a 10 # sack with 100 #;s of potatoes, then this too will fail.  Swap is meant as a last resort emergency exit, but you were asking the question of what if you don't have swap, it will fail.

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              • 4. Re: Running with no swap?
                gabriela..zorrilla

                Great, thanks!

                • 5. Re: Running with no swap?
                  Toby Erkson

                  Gabriel A. Zorrilla wrote:

                   

                  ...8gb per core of swap you say? classic Tableau. Want more safety, more performance? Sure, just add more cores, more ram and in this case, more swap! Optimizing the app? Why bother?

                   

                    I wasn't sure what you were talking about so I looked it up:  http://www.differencebetween.info/difference-between-virtual-memory-and-swap-memory

                  Okay, so we're talking about the lack of physical memory and thus the need to use virtual memory/swap memory.

                   

                  Tableau has no "swap" process or service that we as admins can tune via Tableau because it's an OS-driven process (thank goodness).

                   

                  As Jeff said, a rule of thumb is 8GB RAM per core.  If you have huge extracts it would behoove you to increase physical memory so page swapping isn't necessary...this is a basic concept for computers with all software.  If you run an OS that takes up 3GB RAM on a computer with 4GB RAM you're left with 1GB RAM to 'play' with.  If you load an application like Excel it's going to take up a chunk of that measly 1GB, lessening your available memory to fill the workbook with data, giving you an 'Out of memory' error when you haven't even come close to reaching the limits of the software.  This isn't a fault of the software and no amount of optimization will fix it.

                   

                  It kind of goes without saying that if one needs more performance then hardware will generally need to be improved.  My two-cylinder motorcycle is very fast when it's just pulling me along but is utterly useless if I need to pull a camping trailer, thus the need for "more hardware" by using our truck with 8-cylinders, heavy flywheel, four wheels, etc.

                   

                  Gabriel A. Zorrilla wrote:

                   

                  We have a 32gb server, what happens with Tableau on linux if runs out of ram and has no swap to rely on?

                  There is not enough context here.  How much hard drive space?  The page swapping size can't be bigger than the drive and if you're worried about running out of swap space then you need to get a larger hard drive.  Even more so, if you're don't like virtual memory and all this swapping mumbo-jumbo then install more RAM.  These concepts are basic to all software, not just Tableau!

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                  • 6. Re: Running with no swap?
                    gabriela..zorrilla

                    Thanks Toby. I'll do some experiments. Set swapiness to 1, let's see how it goes with big extracts.