Hi there,
I am sure someone may have experienced this at one point but I have put a new WD Red 6TB hard drive to replace a 3 TB drive to find that I have 2 TB unallcoated space.
I had the understanding that 18TB on a Drobo5n would not be its limit so im surprised why I have this.
Is there a fix?
I have a drbo5n latest firmware, 4TB 4TB 6TB 6TB 6Tb
Thank you
Unless you reset your Drobo after the firmware update, you’re still limited to a 16 TB volume. This would account for your missing 2 TB.
** make sure you back up your data…a reset will wipe all your drives **
hi just to follow on from dragon,
if you are going to make a backup and reset with the larger size, then it might be worth adding a verification step in the process. While it might add some more time, its probably worth it, (especially for that much data). if you are on windows then a checksum tool called corz is quite good, where you can essentially create checksums of your existing content on the drobo first, and then copy all your data including those checksums, onto your backup location, and then verifying the checksums there (and could also copy from the backup and verify on the updated drobo afterwards too.)
there are some other slower processes but checksums will at least add a decent amount of verification for you (and have never let me down yet)
Thanks guys
I did actually try a reset before I posted this I should of mentioned… I didn’t make a backup foolishly but I still have this problem.
You must reformat your disk pack under new firmware to get 64TB volume.
(btw please make a backup before any resets) 
Thank you all for the information