Server Fault is a question and answer site for system and network administrators. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

What really is DAC? When is DAC to be used?

share|improve this question

DAC is a connection dedicated to the SQL Server administrator, not to be used by normal connections to the database. This is useful because it allows the administrator to access the server even if there is some problem occurring on the server. He/she can then fix whatever is causing the problem. It is basically the same as a normal connection, but it is preallocated at startup and reserved for admins only.

For example, imagine that a busy production server suddenly stops accepting new connections. The administrator can use the DAC to log on to the server, see which app is using excessive connections, and perhaps kill some of the connections.

Microsoft has a brief description of DAC here.

share|improve this answer

The DAC is a dedicated local connection that always has resources reserved for it. It is intended for situations when the DBMS has wedged to the point that it is not accepting network connections. You can use this to long onto the server and carry out troubleshooting or maintenance tasks.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.