Please advice if precautions needs to be taken for Oracle RAC cluster in case we are doing a network outage change on the virtual layer. We have stopped the applications already which makes connection with the DB and then plan to perform the change. The change will involve a network flip for may be 10-15 minutes on the subnet where my Oracle server resides.
Which network? For RAC, there are two networks, the public network (which your apps use to connect to the database) and the private network (used for node-to-node cluster communications). If you disable the public network, Oracle will work just fine and you don't need to do anything. If you disable the private network, nodes will get evicted from the cluster. It would be better to stop clusterware on all nodes in this case.