While I'm obviously uninvolved, there are several reasons why turning them off might be a hassle. Primarily is that if anything is encrypted, the encryption ke

While I'm obviously uninvolved, there are several reasons why turning them off might be a hassle. Primarily is that if anything is encrypted, the encryption key is currently in memory and the disks are already open - turning the servers off might require reentering details. Alternatively, in a setup of this size, I imagine there'd be no end of redundancy configurations - RAID for individual disk sets, DRBD (/a SAN equivalent) across servers - turning them off would turn all that HA tech off. Meaning that, when you try to bring the system back up, the redundancy implementation might say "oh no, I've lost x peers from my set of n" and fail itself completely. Shrug. I've no doubt explained it badly, but there are good reasons to keep them running. It's not just a case of "pop the hard drive out and use it elsewhere"; the logic associated with keeping 25 petabytes of data would also have to be restored to its current state.