You can check the status using the following query:
--This shows if there is mirroring.
Select * from sys.database_mirroring
--This shows if there are any endpoints.
Select * from sys.database_mirroring_endpoints
-- This shows all endpoints in the server
Select * from sys.tcp_endpoints
--This shows certificates.
Select * from sys.certificates
--This shows users.
Select * from sys.database_principals
You can also check the state of the database mirroring by performing the following steps:
Open SQL Server Management Studio. The SQL Server Management Studio screen displays.
Connect to the principal server.
Right click on the mirrored database. Menu options display.
Choose the Tasks > Launch Database Mirroring Monitor menu option. The Database Mirroring Monitor displays, showing the status of the database that is being monitored.