Use the showcapacity command to display the amount of managed storage for each device, the total amount of managed storage by device type, and the total of all managed storage.
An invocation example:
perfcli showcapacity
The resulting output:
ESS Devices 2105.26884 1921.3964 GB 2105.28019 1600.5969 GB ESS Capacity 3.52 TB SVC Devices 00000200622002F0 70236.766 GB 0000020064800318 10.48576 GB SVC Capacity 70.25 TB Total MDM Capacity 73.77 TB