How does RAC One Node compare with database DR products like DataGuard or Golden Gate?
The products are entrely complementary. RAC One Node is designed to protect a single database. It can be used for rolling database patches, OS upgrades/patches, and grid infrastructure (ASM/Clusterware) rolling upgrades and patches. This is less disruptive than switching to a datbase replica. Switching to a replica for patching, or for upgrading the OS or grid infrastructure requires that you choose to run Active/Active (and deal with potential conflicts) or Active/Passive (and wait for work on the active primary database to drain before allowing work on the replica). You need to make sure replication supports all data types you are using. You need to make sure the replica can keep up with your load. You need to figure out how to re-point your clients to the replica (not an issue with RAC One Node because it’s the same database, and we use VIPs). And lastly, RAC One Node allows a spare node to be used 10 days per year without licensing. Our recommendation is to use RAC or RAC One Node
