How will storage replicate between the RAC nodes in the same DC?

• Below is One Node RAC Setup, where all services are running on any one active node.

• We will use single stare storage and it is visible from both nodes, but only active nodes can access ASM Storage.

• If Active Instance failed (Only instance/server, not Storage), all services will be started on the secondary node and the secondary node can access ASM storage.

What happened if Active Instance node failed?

Oracle RAC One Node will fail over the database instance to another server in the cluster.

What happened if single storage failed?

In this case, we will have to repair Storage system and restore ASM FS from Backup devices or Create ASM Disk and restore database from backup set.

How we can protect from Single Storage Failure?

In this case, we will have to implement redundant storage Arrays to protect Single Storage failure.

How Storage will replicate between the RCA node if nodes are in different DC.

In this case we will have to implement below architrave, it’s called an Extended Distance Cluster.

The following needs to be considered: 

∙ One set of nodes is typically placed in site A 

∙ The other set of nodes is typically placed in site B 

∙ A host-based mirroring solution should be used to host the data on site A and site B and to make sure that the data between the two sites is kept in sync. 

• Disk array-based mirroring solutions generally lead to an active / passive configuration between the sites.

• A fast and dedicated connectivity between the nodes and the sites is required for the Oracle RAC inter-instance communication.

• Using Oracle RAC One Node only would allow for a slightly less powerful connection between the sites, if needed, but is generally not recommended.

Case: What happened if the side failed.

all work can be switch to the secondary available data center that can take over the database's processing with nearly no interruption for most users connected. No Data loss.