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?
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Drobo usable capacity did not increase when larger HDD was swapped in.
- Thread starter Attonine
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I do not know much about the Drobo, but I do know a bit about normal RAID. Does Drobo run normal RAID or some fancy "smart RAID"? If it's normal RAID, then you need to replace every one of your drives as you've just done for the one. Then your space will double. Merely replacing one drive will not increase your capacity. You will have to replace drive 2, wait for it to rebuild, then replace drive 3 and so forth. Make sure you only replace one drive at a time.
It's a "fancy" raid. Actually, I think I've solved the problem. I need to replace 2 of the drives for the Drobo to increase capacity, the reason is that with just the one 2TB drive, the three remaining 1TB drives do not have enough space to protect the increase in data. Therefore, for my configuration, two 2 TB drives need to be used to gain a usable capacity increase. In other words, spend more money!
