What is cold, warm, and hot database backup?

Cold backup is performed when the database and all its associated services are completely shut down. In this state, data does not change, which guarantees absolute consistency and the absence of corruption in the archive. This method is ideal for simple systems where a planned maintenance window and short-term interruption of business processes are acceptable. The main advantage of the method is the ease of implementation, and the disadvantage is the downtime of the production environment.

Warm backup is performed without stopping the DBMS, but with certain restrictions imposed on data modification, such as putting tables into read-only mode. This reduces downtime for users, but can still cause temporary delays in application operation. This approach is used in medium-sized projects where availability is critical, but full hot synchronization is impossible for some reason.

Hot backup is performed in real-time on a running database under load. Systems use transaction logging mechanisms to create exact snapshots of the data state at a specific point in time. Special log replay algorithms are used to restore such copies. This is the standard for modern web applications that require uninterrupted round-the-clock operation.