locked
DAC in a single datacenter design?

    Question

  • Hi guys,

    I'm wondering if I can or should use DAC mode.  I have a single data center, single AD with a 4 node cluster and a FSW.  3 of my servers hold all of my active databases.  1 server, MB4, holds all the passive copies.  MB4 has all local disk (not attached to the SAN).  The reason for this setup it to one day move MB4 to a different building for DR purposes.

    This weekend we had to take the SAN offline for some maintenance.  I shut down the three primary servers but then the cluster service on MB4 failed because it could not obtain quorum.  I see there is no easy way to fix this for a temporary outage.

    I just read that DAC now supports single AD sites.  I was thinking maybe I can activate DAC mode.  Then in the future if the SAN was not available for some reason, or I move MB4 to a different building, that I could mount all the databases on MB4, manually of course.

    Can DAC mode work this way and if  I had it enabled would I have been able to mount my databases during our outage this morning?  Is setting up DAC mode as simple as enabling it with powershell and setting up an alternate witness server?

    Thanks for your help!

    Keivn


    -Kevin

    Saturday, May 05, 2012 2:25 PM

Answers

All replies

  • Sure, why not.

    Im sure you have seen this. You could use for your needs as well:

    http://technet.microsoft.com/en-us/library/dd351049.aspx

    You wouldnt necessarily need to define an alternate file share witness either. Depends if there is an odd or even remaining number of mbx servers in the cluster.

    • Marked as answer by emma.yoyo Friday, May 11, 2012 1:35 AM
    Saturday, May 05, 2012 5:46 PM
  • I think I am going to test it out.  I have an even # of mbx servers so I would need an alternate witness server, right?

    Thanks A_D

    Kevin


    -Kevin


    • Edited by BestBet Saturday, May 05, 2012 7:50 PM
    Saturday, May 05, 2012 7:49 PM
  • I think I am going to test it out.  I have an even # of mbx servers so I would need an alternate witness server, right?

    Thanks A_D

    Kevin


    -Kevin


    Yes, if the end result after forcing quorum on the remaining servers there are an even number of mbx servers, you need a file share witness defined.

    Saturday, May 05, 2012 7:55 PM
  • Saturday, May 05, 2012 7:59 PM
  • Hi Kevin,

    Any updates?

    Please remember to mark the replies as answers if they help and unmark them if they provide no help. If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com.


    Frank Wang

    TechNet Community Support

    Monday, May 07, 2012 9:09 AM