Last modified on 5 April 2013, at 05:54

RAC Attack - Oracle Cluster Database at Home/Service Failover


  1. Login to collabn1 as the oracle user. Create a new service svctest with RAC1 as a preferred instance and RAC2 as an available instance. This means that it will normally run on the RAC1 instance but will failover to the RAC2 instance if RAC1 becomes unavailable.

    collabn1:/home/oracle[RAC1]$ srvctl add service -d RAC
                       -s svctest -r RAC1 -a RAC2 -P BASIC
    collabn1:/home/oracle[RAC1]$ srvctl start service -d RAC
                       -s svctest
    


  2. Examine where the service is running by checking lsnrctl on both nodes and looking at the SERVICE_NAMES init parameter on both nodes.

    collabn1:/home/oracle[RAC1]$ srvctl status service -d RAC -s svctest
    Service svctest is running on instance(s) RAC1
     
    collabn1:/home/oracle[RAC1]$ lsnrctl services
    Service "svctest.vm.ardentperf.com" has 1 instance(s).
      Instance "RAC1", status READY, has 2 handler(s) for this service...
        Handler(s):
          "DEDICATED" established:0 refused:0 state:ready
             REMOTE SERVER
             (ADDRESS=(PROTOCOL=TCP)(HOST=collabn1.vm.ardentperf.com)(PORT=1521))
          "DEDICATED" established:0 refused:0 state:ready
             LOCAL SERVER
     
    collabn1:/home/oracle[RAC1]$ ssh collabn2
    Last login: Sun Aug  3 13:13:16 2008 from collabn1
    The Oracle base for ORACLE_HOME=/u01/app/oracle/product/11.2.0/db_1 is /u01/app/oracle
    Set environment by typing 'oenv' - default is instance RAC1.
    collabn2:/home/oracle[RAC2]$ lsnrctl services
     
    collabn2:/home/oracle[RAC2]$ lsnrctl services
    Service "svctest.vm.ardentperf.com" has 1 instance(s).
      Instance "RAC1", status READY, has 1 handler(s) for this service...
        Handler(s):
          "DEDICATED" established:0 refused:0 state:ready
             REMOTE SERVER
             (ADDRESS=(PROTOCOL=TCP)(HOST=collabn1.vm.ardentperf.com)(PORT=1521))
     
    SQL> col value format a60
    SQL> select inst_id, value from gv$parameter where NAME='service_names';
     
       INST_ID VALUE
    ---------- ------------------------------------------------------------
             1 svctest, RAC.vm.ardentperf.com
             2 RAC.vm.ardentperf.com
    


  3. Use SHUTDOWN ABORT to kill the instance where service svctest is running.

    SQL> show user
    USER is "SYS"
    SQL> select instance_name from v$instance;
     
    INSTANCE_NAME
    ----------------
    RAC1
     
    SQL> shutdown abort;
    ORACLE instance shut down.
    SQL>
    


  4. Wait a few moments and then repeat step 2. What has happened?

    collabn1:/home/oracle[RAC1]$ srvctl status service -d RAC -s svctest
    


  5. Restart the instance that you killed.

    collabn1:/home/oracle[RAC1]$ srvctl status database -d RAC
    Instance RAC1 is not running on node collabn1
    Instance RAC2 is running on node collabn2
    collabn1:/home/oracle[RAC1]$ srvctl start instance -d RAC -i RAC1
    collabn1:/home/oracle[RAC1]$ srvctl status database -d RAC
    Instance RAC1 is running on node collabn1
    Instance RAC2 is running on node collabn2
    collabn1:/home/oracle[RAC1]$
    


  6. Repeat step 2. Where is the service running now?

    collabn1:/home/oracle[RAC1]$ srvctl status service -d RAC -s svctest
    


  7. Manually failover the service. Confirm where it is now running. Note that this does not disconnect any current sessions

    collabn1:/home/oracle[RAC1]$ srvctl relocate service -d RAC -s svctest -i RAC2 -t RAC1
    collabn1:/home/oracle[RAC1]$ srvctl status service -d RAC -s svctest