5 Replies Latest reply: Dec 26, 2012 8:04 PM by onedbguru RSS

    Oracle11g r2 Grid/RAC SCAN VIP failover

    879152
      Dear Experts and Gurus

      Our Platform: 2-Node ORACLE11G r2 RAC/GRID 11.2.0.1.0 ( hp-ux)


      We have not available the DNS Server for used to SCAN feature of Oracle11g r2 GRID/RAC.

      we have successfully deployed the the setup using scan-vip in /etc/host in our production site.

      we want to used the Oracle11g r2 Grid/RAC

      node1 instance_name dcpdb1 and node2 instance_name dcpdb2

      plz find the default configurations of my setup.

      cat /etc/hosts
      #public
      xxx.xxx.0.1 xyz-ch-aaadb-01
      xxx.xxx.0.2 xyzl-ch-aaadb-02

      #Virtual
      xxx.xxx.0.3 xyz-ch-aaadb-01-vip
      xxx.xxx.0.4 xyz-ch-aaadb-02-vip

      #Private
      10.10.0.1 xyz-ch-aaadb-01-priv
      10.10.0.2 xyz-ch-aaadb-01-priv

      #Scan
      xxx.xxx.0.5 rac-scan

      cat listener.ora
      listener.ora in both the RAC nodes

      LISTENER=(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=IPC)(KEY=LISTENER)))) # line added by Agent
      LISTENER_SCAN1=(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=IPC)(KEY=LISTENER_SCAN1)))) # line added by Agent
      ENABLE_GLOBAL_DYNAMIC_ENDPOINT_LISTENER_SCAN1=ON # line added by Agent
      ENABLE_GLOBAL_DYNAMIC_ENDPOINT_LISTENER=ON # line added by Agent

      cat tnsnames.ora.
      dcpdb =
      (DESCRIPTION =
      (ADDRESS = (PROTOCOL = TCP)(HOST = rac-scan)(PORT = 1521))
      (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = dcpdb.abc.cm)
      )
      )

      problem:
      1. From client 11g r2 I can connect both instance by above tnsnames.ora.
      for testing node failover:
      when I reboot node1 connected session from node1 is not shifted to node2 ( node2 is up).
      similarly when node2 is reboot node2 connected session is not shifted to surviving node node1. instead message show oracle not connected.

      how to resolve this issue by using scan ip?
        • 1. Re: Oracle11g r2 Grid/RAC SCAN VIP failover
          854058
          Are your vips failing over to other node after shutting down one node?

          after reboot check the status of resources... (crsctl stat res -t)
          • 2. Re: Oracle11g r2 Grid/RAC SCAN VIP failover
            Maran Viswarayar
            You should not have the SCAN-VIPS configured in your /etc/host file


            whats the value of REMOTE_LISTENER param value
            • 3. Re: Oracle11g r2 Grid/RAC SCAN VIP failover
              onedbguru
              If you do not have DNS, how do you expect your client to find your scan IP address? that would require it to be in every client you expect to connect to the server. Now, the kicker, in my testing, it appears that you can do the install with /etc/hosts, but in real operation the mechanism used by scan uses gethostbyname - which is DNS only and does not look at /etc/hosts - regardless of your setting for resolv.conf. Not sure about how it works on HP-UX.

              if you do not properly configure your environment, you can expect a LOT of unexplained problems in the future.
              • 4. Re: Oracle11g r2 Grid/RAC SCAN VIP failover
                JaydeepNandy
                What I understand is SCAN is not present in DNS, whereas it's a mandate for SCAN IPs (3 IPs registered against same DNS-entry, which get resolved in a round robin fashion when the DNS-entry is pinged). Believe me, you can play with local hostname resolution and escape pre-req checks on installer screens, or with environment variables (like IGNORE_PREADDNODE_CHECKS=Y) whenever you come across a DNS resolution failure - but, you will not find all the blessings of SCAN.
                You can always try avoiding the necessity of SCAN with "/etc/hosts" (or its Windows equivalent):

                #Scan
                xxx.xxx.0.5 rac-scan
                xxx.xxx.0.6 rac-scan
                xxx.xxx.0.7 rac-scan

                I would recommend you to reach out your network admin and get such SCAN setup done for you in DNS.

                In case you are getting an ORA-03113 with the failover, considering the non-availability of DNS entries for SCAN, there might be a need to configure TAF like we used to do earlier. That is...

                1. Add a service and start it:

                $ srvctl add service -d <db_unique_name> -s <service_name> \
                -r "<preferred_list>" [-a "<available_list>"] -P BASIC

                $ srvctl start service -d <DB_NAME> -s <SERVICE_NAME>


                2. And on TNS file...

                dcpdb =
                (DESCRIPTION =
                (ADDRESS = (PROTOCOL = TCP)(HOST = xyz-ch-aaadb-01-vip)(PORT = 1521))
                (ADDRESS = (PROTOCOL = TCP)(HOST = xyz-ch-aaadb-02-vip)(PORT = 1521))
                (CONNECT_DATA =
                (SERVER = DEDICATED)
                (SERVICE_NAME = *<service_name>*)
                *(FAILOVER_MODE=(TYPE=SELECT)(METHOD=BASIC)*)
                )
                )


                Thanks,
                Jaydeep
                • 5. Re: Oracle11g r2 Grid/RAC SCAN VIP failover
                  onedbguru
                  Jaydeep Nandy wrote:

                  You can always try avoiding the necessity of SCAN with "/etc/hosts" (or its Windows equivalent):

                  #Scan
                  xxx.xxx.0.5 rac-scan
                  xxx.xxx.0.6 rac-scan
                  xxx.xxx.0.7 rac-scan
                  Uhh... No!!! You cannot put multiple names in /etc/hosts that resolve to different IP addresses. This file is searched in a begin-to-end fashion and will ALWAYS resolve to the first IP address.