How to move Time Machine backup from one Drobo to another?

I’m in the position of having to move an extensive Time Machine backup database from one Drobo to another. On the source Drobo, it’s not the only thing on the partition, so a block copy is out of the question. I also question whether this would be a good idea anyway, given Drobo’s thin provisioning.

Drag and drop? Rsync? Anyone ever done this? I’m going to have three weeks to get it right before I have to commit, so I can experiment some.

Dating site :
http://goo.gl/pdQru