1. MySQL Cluster
MySQL Cluster is a highly practical and highly redundant version of MySQL suitable for distributed computing environments. Cluster in Chinese means "cluster". It uses the NDB Cluster storage engine, allowing multiple MySQL servers to run in one Cluster.
MySQL Cluster is a technology that allows deploying a cluster of "in-memory" databases in a shared-nothing system. Through the shared nothing architecture, the system can use cheap hardware and has no special requirements for hardware and software. Also, since each component has its own memory and disk, there is no single point of failure.
1. MySQL cluster architecture
SQL node: Provide sql access to the upper application layer.
Management Node (MGM): Manages the entire cluster. Start, shut down the cluster. Start the cluster with the ndb_mgmd command
Storage/Data Node: Save the data in the cluster. Data nodes, which can provide replicas. Achieve data redundancy.
NDB engine: It is an "in-memory" storage engine, which has the characteristics of high availability and good data consistency.
NDB engine introduction:
MySQL Cluster uses a dedicated memory-based storage engine - NDB engine, which has the advantage of fast speed and no disk I/O bottleneck, but because it is memory-based, the size of the database is limited by the total memory of the system , If the MySQL server running NDB must have enough memory, such as 4G, 8G, or even 16G. The NDB engine is distributed. It can be configured on multiple servers to achieve data reliability and scalability. In theory, the entire data can be realized by configuring two NDB storage nodes.