What types of data replication methods exist?

There are several main types of data replication methods:

1. Synchronous replication — data is written simultaneously to the primary and backup servers. This ensures high consistency but may reduce performance due to delays.

2. Asynchronous replication — data is first written to the primary server, then copied to the backup with some delay. It increases performance but may lead to temporary inconsistency.

3. Master-master (bidirectional) replication — both nodes can accept writes and synchronize with each other. Conflict resolution is required.

4. Master-slave (unidirectional) replication — one node is primary, others only read data.

5. Transactional replication — copies transactions from the transaction log, often used in databases.

6. Snapshot replication — copies data entirely at a specific point in time.

The choice of method depends on requirements for consistency, performance, and availability.