Drobo

No new space after adding 2 drives

Hi

My Drobo FS had 5 x 2TB drives. It was running out of space so i added a 4TB drive. When that was added, it did not update the capacity. I added an additional 4TB drive. That has now been fully added and I still have no additional space. So now I have 2 x 4TB and 3 x 2 TB and only have 5TB usable space.

hi gkonheiser,

can you remember if you are using single SDR drive redundancy mode (which i think is the default mode for the drobofs) or if you are using dual DDR mode?

usually, if you use SDR, then the size of your largest drive (overall) is used for protection
and if you use DDR then the size of your 2 largest drives (overall) are used for protection.

if you have 4TB + 4TB + 2TB + 2TB + 2TB = 14TB raw
14TB (-4TB for sdr) = approx 10TB actual
10TB (*0.9 for filesystem overheads) = approx 9TB

if you can see about 9TB as usable space then you would be on SDR mode
but just to show the full breakdown for DDR too…

if you have 4TB + 4TB + 2TB + 2TB + 2TB = 14TB raw
14TB (-4TB and -4TB for ddr) = approx 6TB actual
10TB (*0.9 for filesystem overheads) = approx 5.4TB

it looks like you are using DDR mode, since you mentioned having about 5TB, so i think you will need to upgrade 1 more drive to actually get some more usable space.