7 Replies Latest reply on May 28, 2015 6:36 AM by AmitGargOCE

    Swap size in R12.1.3 (11gR2) for RHEL 6( 64 Bit)

    2934298

      Hi All,

       

      we are having two node system,

       

      In database server,physical ram is 1TB and swap size is 8G

      In application server,physical ram is 251G and swap size is 3G

       

      Is this configuration ok?? How someone set this & by what basis it should be set?

      Also Database

      SGA is 10G

      pGA-3G

       

      Thank you:)

        • 1. Re: Swap size in R12.1.3 (11gR2) for RHEL 6( 64 Bit)
          Srini Chavali-Oracle

          Recommendations for swap size are in MOS Doc 169706.1

           

          For database initialization parameters, see guidelines in Section 9 of MOS Doc 396009.1

          • 2. Re: Swap size in R12.1.3 (11gR2) for RHEL 6( 64 Bit)
            Bashar.

            Hi,

             

            Based on the document mentioned by Srini, the swap on the db tier should be 16 GB.

            You can set it to 16 GB on the application tier as well if you want.

             

            Do you have any other services running on the db tier??

            Can you post the output of the command "free -m" by running it on both tiers?

             

            Regards,

            Bashar

            • 3. Re: Swap size in R12.1.3 (11gR2) for RHEL 6( 64 Bit)
              2934298

              Hi Bashar,

               

              Kindly find the below output for db

              [oraprod@QAAPPS ~]$ free -m

                                     total       used       free     shared    buffers     cached

              Mem:         1031683     947327     84355         0      431       903633

              -/+ buffers/cache:           43263      988420

              Swap:             8195        2275       5920

               

              for apps

               

              [applprod@QAAPPS ~]$ free -m

                                total       used       free     shared    buffers     cached

              Mem:         251         119         132          0        0         96

              -/+ buffers/cache:       22          229

              Swap:             3           0           3

               

              Thank you:)

              • 4. Re: Swap size in R12.1.3 (11gR2) for RHEL 6( 64 Bit)
                2934298

                No we don't have other services running on db

                • 5. Re: Swap size in R12.1.3 (11gR2) for RHEL 6( 64 Bit)
                  Bashar.

                  Hi,

                   

                  You only have 251 MB of memory on the application server and 1 TB on the db server!

                   

                  The db tier's memory is way over estimated!

                   

                  What is the maximum number of database sessions at any point in time?

                   

                  Regards,

                  Bashar

                  • 6. Re: Swap size in R12.1.3 (11gR2) for RHEL 6( 64 Bit)
                    2934298

                    Hi Bashar,

                     

                    it was in GB,by mistake i wrote m

                    [applprod@QAAPPS ~]$ free -g

                                      total       used       free     shared    buffers     cached

                    Mem:         251         119         132          0        0         96

                    -/+ buffers/cache:       22          229

                    Swap:             3           0           3

                    • 7. Re: Swap size in R12.1.3 (11gR2) for RHEL 6( 64 Bit)
                      AmitGargOCE

                      First of all, your DB (1 TB) & APP (256 GB) machines are over sized in term of memory. What else is running on Server (give top command output)? As you mentioned your DB memory requirement is only 13 GB (SGA + PGA), I will recommend to start with following configuration

                       

                      DB: 64 GB RAM and 16 GB SWAP and increase as you glow (You can keep 1TB if there are other software usage which I don't know)

                      APP: 32 GB RAM and 16 GB SWAP and increase as you glow (You can keep 256 GB if there are other software usage which I don't know)


                      Actual used memory on DB = Used - Cached = 947327 - 903633 = 43694 (~41 GB)

                      Actual used memory on APP = Used - Cached = 119  - 96 = 25 GB

                       

                      Provide "cat /proc/meminfo" ,  "cat /proc/cpuinfo" , and "top" command output to provide you further recommendations

                       

                      Thanks

                      Amit