Explain the mechanism of synchronous data replication in information storage systems.

Synchronous data replication is a mechanism where data write is considered complete only after the data has been successfully written to all replicas.

How it works:

1. The client sends a write request.
2. The primary node (master) writes the data locally.
3. Then the master sends the data to the replicas.
4. The replicas confirm successful writing.
5. After receiving confirmations from all replicas, the master informs the client of the successful operation.

Advantages:

• Ensures that all replicas contain the same data.
• Increases reliability and fault tolerance.

Disadvantages:

• Increases write latency due to waiting for confirmations.
• Requires a stable and fast network connection between nodes.

Example: In distributed databases, synchronous replication ensures data consistency between nodes in real-time.