I have a 2nd Gen Drobo (firewire) which for the last 3 years or so has been happily working away with 4x1TB western Digital Green drives. Saturday I replaced one of these drives with a Western Digital Green 2 TB drive. For 50 hours the Drobo worked away rebuilding itself and finally completed today. However........the usable capacity hasn't increased, only the space reserved expansion. I originally set-up the Drobo as a 16TB device, and it is seen as such by disc utility (actually Disc utility sees it as a 17.58TB device for some reason, but everything else reports it as 16TB and it works ok), Drobo dashboard sees the correct array of disks, everything seems OK, except the usable capacity did not increase. I have looked around the web and can't find anything like this happening, does anyone have any suggestions?