gdgt

I don't understand your question -- I also have a 1st gen Drobo that works fine with OS X Lion when plugged in via USB.

Since you posted this question on the Drobo FS form, I'm going to assume you want to move your data from the 1st gen Drobo you mention to a Drobo FS. You can't move a disk pack from the 1st gen Drobo to the Drobo FS -- they use a different pack format. You need to copy the data manually. If you moved the disk pack already, the Drobo FS would probably refuse to write to the disks, but if it didn't, your data is most likely gone.

If I understand correctly, you have two 1TB drives on the Drobo and you're using 500GB of it. Two 1TB drives translates to 1TB of available storage on the Drobo. You can safely remove one disk from the disk pack on the Drobo without losing data, although the Drobo will go into "emergency" mode because (a) you'll be using more than 95% of your available capacity on the remaining drive and (b) it will be unable to do disk-redundancy.

With the Drobo in emergency mode, you can still read your data. Put the removed drive into the Drobo FS, which will give you 500GB of storage on the new Drobo. Then copy the data from the old Drobo to the new Drobo. When the copy's done, remove the disk from the old Drobo and insert it into the Drobo FS. The Drobo FS will rebuild a 1TB mirror and you'll have transitioned the data.

Because the Drobo slows *way* down after reaching 95% capacity, the device-device copy will take a long time. Be patient and let it do its thing. Use a copy mechanism that allows you to restart in the middle like rsync, Carbon Copy Cloner (for Mac) or robocopy (for Windows).