Enable Write-Caching on a Server 2012 Essential (or any Domain Controller)

Once a server is promoted to a DC, write cache is disabled by default. You can try to enable it, but it will revert back to disabled after a reboot. This is default and can’t theoretically not be changed. It’s done to protect the AD database as well as improve AD DC performance. There is however a registry tip that can force the server to keep that setting.

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I did experience this on my Server 2010 Essentials which is out-of-the-box a Domain Controller. Although not impossible, it’s not recommended to uninstall the DC feature from a Server 2010 Essentials. It’s not easy and various features could stop to run (More info here and here).
The write-Caching was disabled after a reboot only on the System Disk. Not on any other disk in the server… I finally read it was the default behavior for servers with a Domain Controller and found tips here:
  1. One option is to re-enable write-caching at boot with a script using dskcache. E.g.:

    c:\dskcache.exe +w


  2. also a hack that can be made in the registry and works really fine:

    Path: HKLM\System\CurrentControlSet\Services\NTDS\Parameters
    Value: “DSA Heuristics”
    Type: REG_SZ
    Setting this to “1” (Note: the type MUST be a string type) prevents AD service from disabling write cache.




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