mother !#¤"&&#.
Some smart asshole I work with decided it was a good idea to have electricians come work on the main building and cut assorted power without warning IT. Logically, things went down. Now, all our servers are on a massive UPS. but our network stuff isn't. I ordered one a while back, but not enough hours in the day to get it up and running (that part is mea culpa admittedly.)
so when the electricians cut power to the server room... of course the network goes down, and while the physical servers are fine, several of the VMs run on linux, and our Unity storage solution is connected to the physical hosts via the network, and those do NOT like losing connection. FML.