Power issues caused the May 16, 2014 downtime, as stated in Stack Exchange Primary Data Center Offline - May 16th, 2014

What happens when you plug a UPS into itself? , a post for a picture contest, talks about it being caused by a UPS being plugged into itself.

I know that the photo in the post itself is a joke. But was the failure being caused by a UPS being plugged into itself also a joke, or real?

Yes, plugging a UPS into itself sounds like a pretty stupid mistake to make, but I assume it's possible when you've got a large and complex system.


1 Answer 1


As Nick tweeted: (NSFW language warning)

Turns out our "independent" power feeds which we built full redundancy behind all went to the same (now failing) UPS. One. Fucking. Job.

So as far as I can tell, it was due to connecting all feeds to a single UPS which failed, then when the power went down, all servers went down as well.

  • 10
    Yeah, though this isn't quite plugging a UPS to itself, that's close enough to have made a good joke. The DC power architecture we have was only done with redundancy in mind as we believed we were getting two redundant power supplies - that both came from one UPS was an unwelcome surprise.
    – Oded
    May 22, 2014 at 9:39
  • @Oded thanks, and hope you (well, not you personally ;)) hired a good lawyer for a lawsuit against those who dared lying! :-) May 22, 2014 at 10:21
  • 9
    Oded doesn't sue. Oded visits.
    – Bart
    May 22, 2014 at 10:28
  • Only as last resort, @Bart. :) May 22, 2014 at 10:33
  • Small nitpick, the verb is "tweet", not "twit". Twit has a whole different meaning altogether.
    – user163250
    May 28, 2014 at 1:11
  • @Cupcake totally right, what a shame! ;) May 28, 2014 at 4:55

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