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Drobo Dashboard
The screen shots that follow are from the Drobo Dashboard application.
Capacity
The simple view. In OS X Finder terms where TB = 1000^4 and the usable space is 15.93TB.

Drobo Dashboard breaks down the storage usage as shown below.
The 14.49TB Drobo Dashboard figure does not match the 16.0TB (TB = 1024^4) volume size that diglloydTools DiskTester sees, which also matches the Finder” 17.59TB (TB = 1000^4).
What’s odd is that the actual volume actually 16.0TB (1024^4), which is larger than what 4 X 4TB can support. So the 14.49TB figure is accurate, but the volume is created claiming 16.0TB, so write errors will occur past the 14.49TB mark. This is the approach Drobo has taken in the past for expansion; it seems to me a bug when using 5 X 4TB drives, since no more expansion is possible. Using more than 14TB of the capacity is not a good plan in any case.

Status
Green s good. The strength of the Drobo produces are easy to understand green (and if something goes wrong) red lights.

Volumes
The volume list. One can use Disk Utility to partition the Drobo also.

Tools
Various.

Drobo Dashboard preferences
Configure as desired.

Drobo Dashboard general settings
Here is where one can use two drives instead of one for redundancy.
