7 Replies Latest reply: Nov 8, 2012 8:23 AM by mseberg RSS

    what is the role of Lns process in oracle 10g data guard

    972755
      Hi ,
      plz help me out to find out the actual working of lns process in oracle 10g data guard

      when i use SYNC redo transport

      the output of v$managed_stanbdy is like that ..

      PROCESS PID STATUS CLIENT_PROCESS GR# SEQ#
      --------- ---------- ------------ -------- ---------------------------------------- ----------
      ARCH 9258 CLOSING ARCH 2 498
      ARCH 9260 CLOSING ARCH 1 499
      ARCH 9262 CLOSING ARCH 2 496
      ARCH 9264 CLOSING ARCH 1 497
      LGWR 9206 CLOSING LGWR 2 482

      its not display any info about lns,thats means lns is not working in SYNC redo transport mode ?

      but if i changed it to ASYNC then the out put of v$managed_stanbdy is like this ..


      PS PID STS CPS GR# SEQ#
      --------- ---------- ------------ -------- ---------------------------------------- ----------
      ARCH 9258 CLOSING ARCH 1 509
      ARCH 9260 CLOSING ARCH 2 510
      ARCH 9262 CLOSING ARCH 1 505
      ARCH 9264 CLOSING ARCH 2 508
      LGWR 9206 CLOSING LGWR 1 503
      LNS 10528 CLOSING LNS 2 510

      Now it display all the info about lns process...

      i read in oracle documentation that lns process send redo data from primary,( through network service ) to RFS on standby side.

      but first output means that lns is not working,if not then which process send redo from primary to RFS on standby ?

      i also read in some blog that lgwr use some extra buffer size from primary db SGA ,to write redo in that buffer ,ans lns read redo from that buffer and send it to RFS on stanby side,

      i m totally confused ..can u plz help me with correct logic behind this .

      thanx in advance.
        • 1. Re: what is the role of Lns process in oracle 10g data guard
          teits
          hello,

          http://www.datadisk.co.uk/html_docs/oracle_dg/architecture.htm

          read above...i will paste precise answer here shortly.


          Tobi
          • 2. Re: what is the role of Lns process in oracle 10g data guard
            Shivananda Rao
            Hello,

            On the primary database when you run the v$managed_standby, it shows up the LNS process as this process sends redo info to the standby database and on the standby database the RFS process receives the redo information.

            So on the primary database when you query the v$managed_standby, it shows up LNS and on the standby database when you query the v$managed_standby it shows up RFS. Please let us know where you are running the query.

            Refer this http://datadisk.co.uk/html_docs/oracle_dg/architecture.htm
            969752     
                 
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            • 3. Re: what is the role of Lns process in oracle 10g data guard
              972755
              hello ,this output if from primary db only..

              first one is when redo transport set to SYNC

              at primary:-

              SQL> show parameter log_Archive_dest_2

              NAME TYPE VALUE
              ------------------------------------ ----------- ------------------------------
              log_archive_dest_2 string SERVICE=cdssty LGWR SYNC VALI
              D_FOR=(ALL_LOGFILES,PRIMARY_RO
              LE) DB_UNIQUE_NAME=cdssty



              at primary:-

              and second output when redo transport set to ASYNC

              SQL> show parameter log_Archive_dest_2

              NAME TYPE VALUE
              ------------------------------------ ----------- ------------------------------
              log_archive_dest_2 string SERVICE=cdssty LGWR ASYNC VALI
              D_FOR=(ALL_LOGFILES,PRIMARY_RO
              LE) DB_UNIQUE_NAME=cdssty


              in log_Archive_Dest_2 on primary db spfile.
              • 4. Re: what is the role of Lns process in oracle 10g data guard
                mseberg
                LNS reads the redo being flushed from the redo buffers by the LGWR and performs a network send of the redo to the standby site. The main purpose of the LNS process is to alleviate the LGWR process from preforming the redo transport role.

                Best Regards

                mseberg
                • 5. Re: what is the role of Lns process in oracle 10g data guard
                  972755
                  HI thanx for ans ,
                  but i m still not clear ,
                  plz check the output of v$managed_standby in my first post,

                  why i m not getting any info about lns when log transport is SYNC, from v$managed_standby

                  but when i set its to ASYNC i m geting info about lns from v$managed_standby

                  plz clear it ..why its happ..
                  • 6. Re: what is the role of Lns process in oracle 10g data guard
                    LaserSoft
                    Hi

                    Data Guard 11g ASYNC Enhancements :

                    ASYNC behavior has varied over previous Data Guard releases. The LNS process in Data Guard 11g ASYNC now reads directly from the redo log buffer, but unlike pre-10.2 releases,
                    there is never a “buffer full” state that can cause transmission to terminate. Instead, the LNS process seamlessly transitions to read and send from the online redo log of the primary
                    database. Data Guard 11g ASYNC is also more efficient in how it utilizes available network bandwidth, increasing the network throughput rate that can be achieved for any given
                    bandwidth. The higher the network latency, the greater the gain in network throughput compared to previous Data Guard releases.

                    That's the reason it is showing LNS process in output-2.

                    Hope it is clear.

                    Thanks
                    LaserSoft
                    • 7. Re: what is the role of Lns process in oracle 10g data guard
                      mseberg
                      Well it is to me.

                      Thank you for adding so much value to this forum.

                      Best Regards

                      mseberg