2nd Gen Drive Limitations

Hi, I have a 2nd Gen 4 bay Drobo. I have 4, 3tb drives in it now. But I only have about 1.11 tb of space left. The unit is suggesting I increase my space. I was reading in the FAQ that the 2nd gen is limited to 4 TB drives, is that still the case or has there been any firmware updates to increase the capacity?


The Gen2 Drobo has not been officially tested with drive sizes above 4TB, and firmware is frozen at version 1.4.2 for this model, but using larger drives may still be possible. I have placed a 6TB drive in mine momentarily and it recognized it just fine, but I did not leave it in place to verify performance.

Just this morning I replaced a 750GB drive in my Gen2 Drobo with a 6TB drive. It reporting the drive size and the proper available capacity with no issues…so far. It will take a couple more days before the rebuild is completed.

I have 2x8TB, 2x4TB in my Drobo 2nd Gen.

(just linking to your prep-thread)

That’s awesome eza!

I’ve been successfully running my Drobo Gen 2 with 2x 6 TB drives and 2x 4TB drives for a long time - since October 2015 - without any issues [so far, touch wood!].

I’m about to replace one of the 4TBs with a new 6TBs as I’m starting to run low on space…
The original two are:
HGST Deskstar NAS 3.5" 6TB 7200 RPM 128MB Cache SATA 6.0Gb/s High-Performance Hard Drive for Desktop NAS Systems
and the third is a:
WD Red 6TB NAS Hard Disk Drive - 5400 RPM

Has anyone run into a problem not being able to slide out a HD? I have been using a WD RED 5 TB for about 6 month to a year, and today I tried to slide it out and it won’t slide out: stuck in Bay 1 in Drobo Gen 2 Firewire. The HD would slide out 1/4 of a inch then get stuck. My set up: WD RED 5TB / WD RED 4TB / WD Green 2TB / WD RED 2TB.

Are these Drobos running with multiple 8TB and 6 TB drives seen as one volume? I know that when I set up my Drobo, 16 TB is the max for each volume. Is the 16 TB the total number of physical hard drive space? Or is the total number of storage after drobo allocate safe storage between the four hard drives (capacity seen in the dashboard)?

hi ticzon1, just linking to your other post which has some more info about a stuck drive:

I have a heck of a time trying to remove my 6TB HDs from my Gen 2 Drobo. They only slide almost half-way out then hang up. It takes a lot of back and forth, lift, twist,back and forth… Once it’s half-way out, pressing the grey release tab doesn’t seem to make any difference.

hi macgui,
have the drives been running recently? if so, they might contract a bit after cooling down and may be easier to slide out?