We have 3 Operating Modes in DB Mirroring.

• High Availability:- High-Availability operating mode is a combination of principle + mirror + witness with SYNCHRONOUS. In Synchronous, The Principal server SENDS the log BUFFER to the mirror server and then WAITS for a response from the mirror server. Witness server will monitor principal & Mirror Server, In case Principal is not available the witness and mirror will decide automatic failover to BRING mirror online.

• High Protection:- High-Protection operating mode is a combination of principle + mirror with Synchronous. The Principal server sends the log buffer to the mirror server and then waits for a response from the mirror server but Automatic failover is not possible.

• High Performance:- High- Performance operating mode runs asynchronously and the transaction safety set to off. The Principal server sends the log buffer but does not wait for a response from the mirror server for acknowledgment. Mirror server can lag behind from principal and cause data loss.