Explain About Principal, Mirror And Witness Servers?

1.	Explain About Principal, Mirror And Witness Servers?
Answer» Principal Server: - One Server serves the DATABASE to client is called Principal server and it having original data. Can have only one Principal Server and it has to be on a separate server. MIRROR Server: - Other server instance acts as a hot or WARM standby server is called Mirror server and it having copy of database. Witness Server: - The witness server is an optional server and it controls automatic FAILOVER to the mirror if the principal becomes unavailable. To support automatic failover, a database mirroring session must be configured in high-availability.

Answer»

Principal Server: - One Server serves the DATABASE to client is called Principal server and it having original data. Can have only one Principal Server and it has to be on a separate server.
MIRROR Server: - Other server instance acts as a hot or WARM standby server is called Mirror server and it having copy of database.
Witness Server: - The witness server is an optional server and it controls automatic FAILOVER to the mirror if the principal becomes unavailable. To support automatic failover, a database mirroring session must be configured in high-availability.

Discussion