The heardware configuration：
For RAC database,include two or more nodes. Redundant power supply,network card,dual CPU and error correction memory.
Shared disks should also have built-in hardware redundancy -multiple power supplies,raid-enabled disks,and so on.
The software configuration:
Cluster Ready Service,CRS
The network configuration:
Each node in RAC has at least three IP addresses.
Public network:All normal connections between the node and the server.
Private network:Intra-cluster node communication.
Virtual IP:Listen for addresses,and support rapid connect-time failover.
Public and private networks are best bond,providing redundancy and bandwidth.
Summary:This blog birefly describes RAC.
NOTE:The next blog will describe the RAC process.
原文：https://blog.51cto.com/11298469/2453121