Shared storage or masterslave replication is used in traditional RDBMS to achieve high availability. The first solution relies on high available hardware, and so are of high cost, while the second solution cannot meet the requirements of strong consistency and high availability concurrently. OceanBase combines cloud computing and database technology. Its high availability solution is based on Paxos protocol. This solution is built on top of commodity machine. It meets requirements of both strong consistency and high availability with low cost.