An Overview of MySQL NDB Cluster
The “Shared Nothing” Architecture and Database Sharding
It is a distributed computing architecture with interconnected, but independent computing nodes with their own memory and disk storage that are not shared. Compared to a centralized controller based distributed architecture, the SN architecture eliminates presence of a “single point of failure”. An SN architecture offers great scalability by adding as many nodes as wanted. The data is distributed or partitioned among the different nodes that run on separate machines. To respond to user’s queries, some kind of coordination protocol is being used. This is also called database sharding, where the data is horizontally partitioned. A database shard that contains a partition will be holding on a separate database server instance to spread load and to eliminate failures. In horizontal partitioning, table rows are separated, rather than as columns in vertical partitioning or normalization. Each data set will be part of the shard that is distributed across different database servers and also at different physical locations, if needed.