Re: Urgent, 2 instances on same server, instance failover scenario..

If you talking about Oracle RAC failover then RAC failover does not fail instances over to another node. The instance on the other node(s) take over all processing. All new connection requests to the Oracle are directed to the available nodes depending on connection failover being configured.

That is if the connection is configured to go instance one, i1, and i1 is unavailable then the connection request fails. But if the connection is configured to connect to instance i1 then i2 the connection will look for i1, find it unavailable, and then connect to i2.

You also have tansparent application failover where if node 1 drops processing of the process can be picked up and continued on another node. But this has to be coded into your applicaion.

Now to more directly answer your question. When you connect to node 2 and do a ps -ef | grep pmon you should see two databases are running.

Change the value of the $TWO_TASK variable, if in use, to the SID or Service Name of the instance you want to connect to and you should be able to get a connection as a regular user. To connect as "sysdba" then also set the value of $ORACLE_SID to the SID for the instance you want to connect to and unset $TWO_TASK.

If you do not know what these environment variable values should be look in the oratab file. You should be able to find the $ORACLE_HOME values there since the two databases could have different homes.

HTH -- Mark D Powell -- Received on Fri Jul 15 2005 - 08:32:45 CDT