This is just a question, but to me it a puzzling one.
Yesterday night while on duty. (I work Fire Rescue ) I went ahead and did a defrag & compact on the ADDS db. I stopped the db using ( net stop ntds ) compacted it and the before I could copy the new ntds.dit to its new location, I got a call, by the time I got back I was locked out of the DC and when I tried to log back in I was not able to b/c AD was not running and they was not log in service. I tried a few more time and gave up think that in the morning I just go in and boot into the DC using restore. This morning to my surprise I was able to log in without any problems and when I checked AD it was running.
Is it suppose to start up by itself?