On DAS drobos, the drobo software is data aware,and the rebuild time is directly related to the amount of data you have on it.
i.e. even if you have huge disks, if you only have 3 or 4 GB of data, the rebuild only takes minutes.
I was surprised to see my new 5N estimating rebuild times of 12 hours when i only had 20Gb on it, i would have expected it to be in minutes.
does the 5N work more like “normal” linux RAID in that it isnt data aware?