NetApp Usable Space Calculator

This calculator computes usable space for NetApp FAS storage system based on disk size and aggregate configuration parameters. Supported RAID levels are RAID 4 and RAID-DP.

RAID Type:
Drive model: 
or Right-Sized capacity (GiB): 
Number of drives per RAID group: 
Number of RAID groups per aggregate: 
WAFL Overhead (%):
Aggregate Snapshot Reserve (%): 
Volume Snapshot Reserve (%): 
Fractional Reserve (%):

Number of RAID groups per aggregate: 1
Number of drives per RAID group:16
Total number of drives per aggregate: 16
Total number of data drives:15
Total number of parity drives:1
Fault tolerance
(disk drives per RAID group):
Drive model:800 GB SSD (X44xA-R6)
Right-Sized drive capacity (GiB):744
Total aggregate space (GiB):11160
Usable aggregate space (GiB):10044
Total FlexVol space (GiB):9541.800
Usable FlexVol space (GiB): 7633.440


If entered, the Right-Sized capacity value overrides the selection from the Drive model list. To use the Drive model list, clear the Right-Sized capacity field.

This tool does not take into account Maximum Aggregate Size parameter which varies between controller models and OTAP versions. Maximum Aggregate Size (64-bit) can be in the range between 120 TB and 400 TB.

For GB vs GiB see Gigabyte (GB) to Gibibyte (GiB) converter.

RAID group sizes for RAID-DP:

Drive Type Default  Max  Min
SATA / BSAS / FSAS / MSATA / ATA:  14 20 3
FC / SAS: 16 28 3
SSD: 23 28 3

RAID group sizes for RAID-4:

Drive Type Default  Max  Min
SATA / BSAS / FSAS / MSATA / ATA:  7 7 2
FC / SAS / SSD: 8 14 2