Re: Many years ago..
A story I'm probably safe to tell now as the resulting insurance claim has been settled.
As some of you may be aware, a couple of years back there was a bit of a problem with rainwater run off in Brisbane. Basically the CBD was a couple of feet underneath it. A major Australian company who will remain nameless has a largish operation there. With the basement flooded an impromptu meeting at Head Office was told:
The local data centre is safe - its located on the 8th floor
The battery backups will definitely keep the whole shebang running long enough for the diesel generators to come on line if the power is cut.
These generators are on the roof, not in the basement which is flooded.
The fuel tanks on the roof have some number of hours fuel before they need to be refilled. This will almost certainly not be enough to get through an outage.
Where are the reserve tanks? In the flooded basement. Oops. Don't worry, we'll get one of the local IT bods to nip in and haul a jerry can or two up to the roof and top the tanks off. How exactly this was going to happen with the CBD effectively shut down was never explained.
As it was the question was moot because the the generators did not power the aircon and the whole thing went into thermal shutdown within 20 minutes of the mains being cut off...