Suggest an editImprove this articleRefine the answer for “What is a database cluster?”. Your changes go to moderation before they’re published.Approval requiredContentWhat you’re changing🇺🇸EN🇺🇦UAPreviewTitle (EN)Short answer (EN)A **database cluster** is a group of servers (or database instances) working **as a single system**, providing shared storage, processing, and data access: the idea behind a cluster isn't one powerful machine, but **several linked nodes** that share the load, storage, and fault tolerance among them. **Key point:** the main types are `master-replica` (one server for writes, the rest for reads), `multi-master` (several nodes can write at once, e.g. Galera Cluster), and `shared-nothing` (each node stores its own data, used with sharding); a cluster synchronizes data across nodes so it stays consistent.Shown above the full answer for quick recall.Answer (EN)ImageA **database cluster** is a group of servers (or database instances) working **as a single system**, providing shared storage, processing, and data access. The idea behind a cluster isn't one powerful machine, but **several linked nodes** that share the load, storage, and fault tolerance among them. ### The main goals of a cluster 1. **Scaling.** It spreads load across several servers, more requests, more data, higher performance. 2. **Fault tolerance.** If one node fails, the rest keep working, preserving the system's availability. 3. **Load balancing.** Requests automatically get routed to free or less-loaded nodes. 4. **Replication and consistency.** The cluster synchronizes data across nodes so it stays consistent. ### Examples of cluster types - **Master-replica (primary-replica).** One server for writes, the rest for reads. - **Multi-master cluster.** Several nodes can write data at once (e.g. Galera Cluster, PostgreSQL BDR). - **Shared-nothing cluster.** Each node stores its own data (used with sharding). ### Example In PostgreSQL, the term "cluster" often refers to **a set of databases managed by a single PostgreSQL server process**. In the broader sense (in production), it means **a physical or logical set of servers** joined by a shared architecture and replication. **Summary:** A database cluster is a "team of servers" that together provide speed, fault tolerance, and scalability, while keeping the data consistent overall.For the reviewerNote to the moderator (optional)Visible only to the moderator. Helps review go faster.