Another great post from RiskContainment called Back Up? What Back Up? about the risk of putting servers in a basement, reminded me of this tale from my past:
I once worked for an international securities dealer in Toronto; we had additional trading desks in Montreal and Vancouver. When I was asked to help with DR planning I learned from the IT guy that the back up server (than handled our trading system) was 6 ft away from the primary server. This was pre 9/11/01, and if the building went down, both servers were down. And while people were thinking that the other two trading desks were natural backup sites, it turns out all trades in Montreal and Vancouver were routed through the Toronto server before going to the Exchange. So if Toronto went down we would have been SOL.