We knew that building a completely new system from top to bottom would bring challenges. But some of them were extremely nontechnical and simply a side effect of our scale. For example, one of our test production runs hit a complete standstill when we realized that the data center personnel simply could not move the racks. Since these racks were a modification of the OpenVault system, we used the same rack castors that allowed us to easily roll the racks into place. But the inclusion of 480 4 TB drives drove the weight to over 1,100 kg, effectively crushing the rubber wheels. This was the first time we'd ever deployed a rack that heavy, and it wasn't something we'd originally baked into the development plan!