What happens if the Domain Controller is down?

  • If the SQL Service is running on a domain account and the DC goes down, will the service still run?

    What about windows authentication, will it used the cached info?

    Thanks.

  • The service will still run and you can still log in.

    Gail Shaw
    Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
    SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

    We walk in the dark places no others will enter
    We stand on the bridge and no one may pass
  • I have heard of databases and sql agent jobs owned by domain accounts having issues when a domain controller is unavailable. The database issues had to do with cross-database ownership chaining so that may not pertain to you. Unfortunately I did not save the links to refer you. At any rate, this is just another reason to have sa own all your user databases. By default I opt to have sa own all my agent jobs and if needed I use proxy accounts to restrict the permissions of specific steps as needed.

    There are no special teachers of virtue, because virtue is taught by the whole community.
    --Plato

  • Sinh Dinh (8/22/2011)


    If the SQL Service is running on a domain account and the DC goes down, will the service still run?

    Typically you will have more than 1 domain controller, so you should be fine. If your domain only has 1 domain controlller the services will still run unless you try to restart them, authentication attempts will also be hampered (i.e. logging into sql server with windows authentication, accessing domain resources, etc).

    Sinh Dinh (8/22/2011)


    What about windows authentication, will it used the cached info?

    Thanks.

    The local SAM is only queried when the machine is disconnected from the domainetwork

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    "Ya can't make an omelette without breaking just a few eggs" 😉

  • Perry Whittle (8/26/2011)


    If your domain only has 1 domain controlller the services will still run unless you try to restart them, authentication attempts will also be hampered (i.e. logging into sql server with windows authentication, accessing domain resources, etc).

    I've often run my home desktop with the DC switched off temporarily. No problems starting SQL, no problems logging in, no problems accessing resources.

    Gail Shaw
    Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
    SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

    We walk in the dark places no others will enter
    We stand on the bridge and no one may pass
  • how are you handling name resolution while the DC is down

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    "Ya can't make an omelette without breaking just a few eggs" 😉

  • The DC is the primary DNS, the ADSL modem is a a secondary DNS, and the SQL Server is local anyway.

    Gail Shaw
    Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
    SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

    We walk in the dark places no others will enter
    We stand on the bridge and no one may pass
  • I think it would depend how long the DC is down for. I can see the machine using cached credentials for a while, but eventually it's going to have to go to the DC for authentication--I have absolutely no idea how long that period would be, though!

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