4 Replies Latest reply on Sep 4, 2017 9:47 AM by Dafydd Griffith

    12c Database, 12.1.3 EBS on Solaris 11 and using AMM?

    Dafydd Griffith

      EBS = 12.1.3

      Database = 12c

      Solaris 11

      64GB of RAM



      We're migrating an Oracle EBS 12.1.3 database from some old servers. The process has been a little painful but we have figured it out and we're now looking at what settings we should use to take advantage of the new server's features.


      We've tried  switching to AMM on some test and development boxes and it seems easy enough. However, whereas the test and development boxes have only a few gig to spare for defining MAX_MEMORY_TARGET and MEMORY_TARGET, we have far more available to use on the production box. We have between 20-30GB to play with to use for the SGA and PGA but have read quite a few articles that this can be problematic if your operating system is using small (4k) buffer page sizes - especially under Linux. The thinking is that you should use ASMM and Huge Pages. However, We're running Solaris 11 and apparently this uses "large pages" by default and the buffer page size is at least 4MB.


      So, my question is, what's the largest recommended size for MAX_MEMORY_TARGET and MEMORY_TARGET on a Solaris 11 given it's 4MB buffer page size? Has anyone tried AMM with at least a  20GB value it in a real world implementation? Or, should I forget the whole thing and just go to ASMM?


      Thanks in advance.

        • 1. Re: 12c Database, 12.1.3 EBS on Solaris 11 and using AMM?

          Hi Dafydd Griffith,


          To address your query generic terms, I would suggest you to refer the following Note

          EBS Database Parameter Settings Analyzer (Doc ID 1953468.1)

          Database Initialization Parameters for Oracle E-Business Suite Release 12 (Doc ID 396009.1)


          I hope this could help to answer your query.




          • 2. Re: 12c Database, 12.1.3 EBS on Solaris 11 and using AMM?
            Dafydd Griffith

            Thanks for that. I've just run it against our current production system (Manual Memory Management) and it suggests that I up the SGA_TARGET from 4GB to 14GB. I can't do that as we don't have the RAM so the server migration is timely!


            As the current system is a RAC server and were moving to a non RAC environment then I suspect I'm looking at a figure of around 20-28Gb for the SGA_TARGET? Obviously I'll have to add on extra for the PGA if I go the AMM route and define MEMORY_MAX_TARGET at around 30-40GB?


            Is 40GB a realistic size for running AMM on a Solaris 11 server or is it just too big if the block size is the default 8k? It's looking like I'm better off going the ASMM and large/huge pages route?

            • 3. Re: 12c Database, 12.1.3 EBS on Solaris 11 and using AMM?

              In my experience, large/huge page plus sga_target always outperforms AMM with EBS.  If you enable AMM, you will see the MMON process running at 100% CPU most of the time trying to guess what the memory allocation should be as the system constantly switches between predominantly transaction processing to long running batch workloads like create accounting or other long running frequent reports.  The pga_aggregate_target parameter is not a limit either.  If you query v$sesstat, you can find individual EBS sessions using more PGA than pga_aggregate target.  If you have hundreds of users, you really need to ensure you have enough free RAM on the server to handle UGA/PGA memory grabs by shadow processes which are outside of ASSM/AMM memory allocations.  Otherwise you can find the server heavily swapping when a long running process suddenly grabs 10-20GB of UGA or PGA.

              • 4. Re: 12c Database, 12.1.3 EBS on Solaris 11 and using AMM?
                Dafydd Griffith

                Many thanks for that.


                If anyone else has an opinion then please express it here. I have a few weeks left before I have to implement this.