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RAC Attack - Oracle Cluster Database at Home/Client Load Balancing

< RAC Attack - Oracle Cluster Database at Home
The latest reviewed version was checked on 6 April 2021. There are template/file changes awaiting review.


Note: This lab was written for 11.1 and does not show the same behavior in 11.2 - it needs to be updated!

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  2. Power on both nodes from the VMware Console. 
    [root@collabn1 ~]# srvctl status database -d RAC
Instance RAC1 is running on node collabn1
Instance RAC2 is running on node collabn2


  3. Open a SQLPlus session on the database and confirm that there are no sessions for the SH user. SQL> select inst_id, count(*) from gv$session where username='SH' group by inst_id; no rows selected
  4. Disable server-side load balancing on both instances by clearing the REMOTE_LISTENER init param and re-registering. Before registering with the listeners, restart them to reset the connection statistics. SQL> alter system set remote_listener=''; System altered. collabn1:/home/oracle[RAC1]$ lsnrctl stop collabn1:/home/oracle[RAC1]$ lsnrctl start SQL> -- instance RAC1 SQL> alter system register; System altered. collabn1:/home/oracle[RAC1]$ lsnrctl services Service "RAC.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 LOCAL SERVER collabn2:/home/oracle[RAC2]$ lsnrctl stop collabn2:/home/oracle[RAC2]$ lsnrctl start SQL> -- instance RAC2 SQL> alter system register; System altered. collabn2:/home/oracle[RAC2]$ lsnrctl services Service "RAC.vm.ardentperf.com" has 1 instance(s). Instance "RAC2", status READY, has 1 handler(s) for this service... Handler(s): "DEDICATED" established:0 refused:0 state:ready LOCAL SERVER
  5. In your other connected SQLPlus session, keep an eye on the balance of connections. At the same time, open a new shell session and run this script which will open 160 connections to the database. a=160; while [ $a -gt 0 ]; do sqlplus sh/sh@RAC & a=$((a-1)) done How were the connections distributed between the database instances during client-side load balancing?
  6. Terminate all of the sqlplus sessions by running these two commands. After you run the second command, press <Ctrl-C> after you start seeing the message "no more job". killall sqlplus while true; do fg; done <Ctrl-C>


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