How many copies of the database are used in your current system?

The number of database copies in the system depends on the architecture and requirements for fault tolerance and performance.

• In simple systems, a single primary database is often used.
• To ensure high availability and scalability, replication is used — creating multiple copies (replicas) of the database.
• For example, in a master-slave architecture, there is one primary (master) database and several replicas (slaves) for reading.
• In distributed systems, there can be multiple master nodes with replicas.

Without specific details about your system, it's difficult to specify an exact number, but it usually ranges from 1 (one database) to several dozen copies in large-scale systems.