Interview Questions -DAC

1)What is a DAC. How do you connect to server through DAC?

This diagnostic connection allows an administrator to access SQL Server to execute diagnostic queries and troubleshoot problems even when SQL Server is not responding to standard connection requests.

This dedicated administrator connection (DAC) supports encryption and other security features of SQL Server. The DAC only allows changing the user context to another admin user.

SQL Server makes every attempt to make DAC connect successfully, but under extreme situations it may not be successful.

To connect to a server using the DAC

In SQL Server Management Studio, with no other DACs open, on the toolbar, click Database Engine Query.

In the Connect to Database Engine dialog box, in the Server name box, type ADMIN: followed by the name of the server instance. For example, to connect to a server instance named ACCT\PAYABLE, type ADMIN:ACCT\PAYABLE.

Complete the Authentication section, providing credentials for a member of the sysadmin group, and then click Connect.

The connection is made.

If the DAC is already in use, the connection will fail with an error indicating it cannot connect.