How to Use SQL Server’s Dedicated Admin Connection (DAC) – Video

You may have heard that there’s a secret back door into your SQL Server– but have you enabled access to it properly? Do you know when you might need to use it, and how you can connect? Kendra Little explains why the Dedicated Admin Connection (or “DAC”) is so important and how to configure remote access.

Don’t have 11 minutes / don’t have YouTube access? Head on over to our blog post on the DAC.

Jeremiah says: I had to use this once. I ran into a low memory situation on a SQL Server and Windows decided to page out SQL Server in the middle of the business day. The system ground to a halt, it was even unresponsive over RDP, and we had to hard power cycle the server (hold down the power button in the server room). I set up the DAC and the next time the issue happened, I was able to jump into the SQL Server, collect information, and then issue a graceful shutdown. This made it easier to diagnose the problem, too.

Brent says: Using the DAC is like knowing how to read the basics of DBCC CHECKDB output. You’re probably never going to need it, but when you do, just ten minutes of preparation will make a world of difference.

Jes says: What Brent said. A few minutes of practice every six months can save minutes or even hours of frustration – and potentially downtime – when faced with a real emergency.

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9 Comments. Leave new

  • When I became a DBA I was told by the senior DBA this was one of my first tasks to learn and be comfortable in using. It saved my life the day I had to connect to an instance which was unresponsive

  • Hello Kendra,

    Nice video.
    I have also written back in 2011 how you can use the DAC to troubleshoot thread pool starvation in SQL Server:



    • Kendra Little
      January 19, 2015 3:56 pm

      Oh, I remembered that you wrote a great post about threadpool, but I forgot that you also included the DAC in it. That is a great post.

  • prince rastogi
    January 20, 2015 9:00 am

    This is one of the first thing which i used in my early days as DBA to solve one interesting issue.

  • Great video once again! You guys rock!

  • Brendan Costigan
    January 24, 2015 10:54 am

    I presume that Dedicated Administrator Connection (DAC) and Data-Tier applications (also know as DAC (for some reason)) are not connected?

  • Alain Martin
    April 13, 2015 2:26 pm

    Hi guys,

    just little comment. The DBAReactions funny video is annoying when you watch you try understand what the main videao try to explain us. Just to let you know, maybe I am not the only one.

    BTW, continue your great work!

    • Kendra Little
      April 13, 2015 2:34 pm

      Oh, you know whenever I’m watching these I hover over the bottom frame and click “view on youtube” so I can make it bigger and get rid of distractions. It’s smart enough to auto-start it wherever you are in the video, and that gives you the ability to watch it in “theater mode” without going completely fullscreen.