https://msdn.microsoft.com/en-us/library/bb727049.aspx?f=255&MSPPError=-2147217396
DCDIAG: How to Check Domain Controller Health:
https://activedirectorypro.com/dcdiag-check-domain-controller-health/
https://u-tools.com/help/Dcdiag.asp
https://community.spiceworks.com/t/dcdiag-errors-on-new-domain-controller/607809
Secondary Controller Server 2008:
https://www.elmajdal.net/win2k8/setting-up-an-additional-domain-controller-with-windows-server-2008/