3 Replies Latest reply: Nov 24, 2013 6:00 AM by mseberg RSS

    Question on Listener in a dataguard environment

    Omega3

      Version: 11.2.0.3

      Platform: Oracle Linux 6.3

      Type: Physical Standby

       

       

      Question1.

      Once a dataguard setup is done , what is the role of listeners in Primary and Physical standbys? The redo transport is not done through listeners. Right ?

       

      Question2.

      In RAC , the listener runs from GRID_HOME. Before I start creating the standby DB, How do i add a static Node Listener in a RAC setup ?

      Can I use netca for this?

        • 1. Re: Question on Listener in a dataguard environment
          mseberg

          Hello;

           

          Q1

           

          Listeners are key for communication with remote databases either Primary or Standby. Right Redo Transport is not done through them, it is a process: ( examples )

           

          ARC0 Archiver

          DMON Data Guard Monitor

          FAL Fetch Archive Log

          LCR: Logical Change Record

          LGWR Log Writer backend process

          LSP: Logical Standby Process aka SQL Apply (logical)

          MRP Managed Recovery Process aka Redo Apply (physical)

          RFS Remote File Server (receives undo)

          TAF Transparent Application Failover

           

          Q2

           

          standby host 1

           

          LISTENER =

            (DESCRIPTION =

            (ADDRESS_LIST =

            (ADDRESS = (PROTOCOL=IPC)(KEY=LISTENER))

            (ADDRESS = (PROTOCOL = TCP)(HOST = standbyhost1-vip)(PORT = 1521))

            )

            )

           

          SID_LIST_LISTENER =

            (SID_LIST =

            (SID_DESC =

            (GLOBAL_DBNAME = STNDBY.MY_DOMAIN)

            (ORACLE_HOME = $ORACLE_HOME)

            (SID_NAME = STANDBY1)

            )

            )

           

          standby host 2

           

          LISTENER =

            (DESCRIPTION =

            (ADDRESS_LIST =

            (ADDRESS = (PROTOCOL = TCP)(HOST = stndbyhost2-vip)(PORT = 1521))

            )

            )

           

          SID_LIST_LISTENER =

            (SID_LIST =

            (SID_DESC =

            (GLOBAL_DBNAME = STNDBY.MY_DOMAIN)

            (ORACLE_HOME = $ORACLE_HOME)

            (SID_NAME = STANDBY2)

            )

            )

           

          Best Regards

           

          mseberg

          • 2. Re: Question on Listener in a dataguard environment
            Omega3

            Thank you.

             

            From googling, I gather that LNS(Log network server) does the Redo transport (at least in 11.2). Any idea which port is it using ?

             

            Following is a typical LOG_ARCHIVE_DEST_2 parameter value where CRDMS_DG is the Tns Entry for the standby DB. You think LNS uses this tnsentry internally to transport redo by creating a normal oracle session through listener ?

             

            If my assumption is wrong , then why do we set TNS entry of Standby DB in LOG_ARCHIVE_DEST_2 ?

             

            log_archive_dest_2=service="CRDMS_DG", LGWR SYNC AFFIRM delay=0 optional .............

            • 3. Re: Question on Listener in a dataguard environment
              mseberg

              Hello again;

               

              LNS ships redo data using Oracle Net Services to the Standby where an RFS process receives it. So whatever port you setup for Oracle Net Services, commonly 1521. You can use NET_TIMEOUT to tune this process and transport attributes like "AFFIRM".

               

              Best Regards

               

              mseberg