True, but I was trying to keep this in the realm of reality. A large org could actually shift this much data in a single day from step A (shutdown/pull drives)

True, but I was trying to keep this in the realm of reality. A large org could actually shift this much data in a single day from step A (shutdown/pull drives) to Z (start using the new cluster on the other side of the world) using this method. Expecting someone to have a million or more SD card readers is not really a practical plan. I could have probably also increased the density by using blue-ray data disks, but having a similar number of optical drives waiting for disks was also not really practical. At one time this general process was how chunks of yahoomail migrated from our original Four11 colo on stanford campus to the yahoo colos in san jose and sunnyvale (except it was netapp drives and shelves packed into my miata instead of a 747 -- 1T of 18G drives with the top down doing 80-90 southbound on 101...fun times :)