Oracle RAC Failover functionality clarification we are running two node active/active Oracle11g R2 RAC cluster i need to replace public network cables on each node. I am planning to do as given below:

Setup: 


OS: oracle Solaris 11.1 Sparc
Database : oracle11g R2 RAC dual node cluster using ASM
Middle tier : Microsoft Dot net apps servers
Client tier :  Internet explorer ( BUI ) 


Public NW Cable replacement Action Plan: 


Prepared and ensured the 2 new Public network cables one for each node
Check and verify the Database status using srvctl
first from node 1 i will remove the cable from both (switch port &amp; server port) 
simultaneously and replace it with the new cable with in few seconds.
Check and verify the instance status on the new cable (node1) and wait for 5 minutes
Repeat the steps 2-3 for the node2.
Check and verify the instance status and wait for some time to ensure the both the 
instacnes are up and running
Test the application


Note: 
Initially check and ensure the Apps servers tnsnames.ora  configuration ( SCAN Names / VIP/node's local ip  ) Using SCAN-Names recommended if not observe carefully the TAF behaviour on the node side and the application side as well )

Kindly review the above steps and guide me.

MShafi - Senior System admin
Abu Dhabi - UAE
Just from Oracle side there is nothing to worry about. You could even do this operation during normal business hours.

BUT! most Applications are not cluster ready. They cannot deal with this situation and will crash. All services are still available since they are migrated to the second node. But the session does not get migrated that's why the client will loose the connection. An application which supports RAC would then reopen the connection and just continue to work. 

I would plan a downtime for this operation.

For the future you could bond two network ports for the public interface in failover mode. With that setup you could do the operation without downtime. Note that bonding in load balance mode does not work so well -- at least this is my experience.