[Xk]

Fine. Assume it's one bit per voxel.

512 petabits = 2 petabytes.

So only 2 petabytes of data. I'd like to see the server that processed those 2 petabytes.

Notch also points out that even still, 8m is quite a small height. Take it to 16m and now you need 4 petabytes of space.

[Robin_Message]

Nope, more like 2 petabytes plus 1 bit. Because almost all of that new top 8m is the same atom (empty air), if they are using an octree to store the voxels, then it would take 1 extra bit to store an empty top 8m. Obviously if there are things in the top 8m, it will take more space, but only for the things that are there.