Explain Principal, Mirror And Witness Servers in DB Mirroring?
Answer»
Principal Server:- The main server HOLDING a primary copy of the database and serving client application & requests.
Mirror Server:- The SECONDARY server which HOLDS a mirrored copy of Principal database and acts as a hot or warm standby server on basis Synchronous & Asynchronous configuration.
Witness Server: - The witness server is an optional server and it CONTROLSAUTOMATIC failover to the mirror if the principal becomes unavailable.