Calculating Capacity to Use

The best way to determine how much usable, protected storage space you will have available for your data, based on the number and capacity of the drives you use in your Drobo device, is to use our Capacity Calculator at

A shortcut to estimating the capacity available for your data is to omit the largest drive and then add the capacity of the remaining drives. If you plan to use Dual Disk Redundancy, omit the largest two drives. For example:

Single Disk (Default) Redundancy


Dual Disk Redundancy



-        Actual capacity is often less than what is shown in the examples above due to the different systems used for rating capacity. This has nothing to do with Drobo devices.

-        Know that all Drobo devices enable you to easily increase storage capacity at any time by simply inserting additional drives or replacing smaller drives with larger ones.

See Also

Managing Capacity (Drive Space)

Adding Capacity (or Drives)

Checking Storage Usage and Device Status Information