Data ONTAP Discussions

NetApp Usable Space Calculator

A very basic version of NetApp Usable Space Calculator. Please provide feedback.


March 18, 2014 - Latest version 2.1 - Minor updates to include some new disks and a few disk calculation bugs


Sep 5, 2013 Update: Software Version 2.1. Minor updates - Added 2 new disk sizes ( 1.2 TB SAS & 4 TB SATA )


Aug 8, 2013 Update: I have updated the software version to 2.0 and fixed some bugs.


Also this includes a new feature called Raid Group Size Estimator where you key in disks values, raid type and disk type - the software will attempt to provide the best RG size values either based on NetApp recommendations or Optimal Capacity.(Please note: The Raid group size input in the calculator is only for disk space calculations and this is ignored for the raid group estimator)

I have developed this Raid Group Size Estimator based on many users request. As usual please provide feedback if you do some testing.


Screenshot of new version 2.1 (Software zip attached to this post)




(The below image is a old version. New version available which is 2.1)



Re: NetApp Usable Space Calculator

Nice work,

Maybe you could also include a visual RG layout + RG disk deficiencies if any. Administrators can tweak the values to get the best results without breaking out the spreadsheets.

Maybe also have the max aggregate sizes per controller model + Ontap version (selections) with an indication if you are over this value.

Can you provide the exact maths behind the workings?


Re: NetApp Usable Space Calculator

Hello..Thanks for the feedback..I will try to do some work based on your feedback when I get some time. For the math and the formulas behind the tool, here is the link -


Re: NetApp Usable Space Calculator

Nice work, thanks!

Re: NetApp Usable Space Calculator

Will this tool consider one or two controllers? How about the max/default RAID size for different type disk?

I could not attach a file, so I send the tool I written to your gmail.

Re: NetApp Usable Space Calculator

There is no assumption on the controllers. Just plain disk calculations. Also for the max/default RAID size, I assume the user using this tool has some idea of the RAID sizes beforehand and will key it in.

Re: NetApp Usable Space Calculator

nice work! thanks for taking the time to do this!

Re: NetApp Usable Space Calculator

Great tool, thanks! Just used it to help management working out a quote for a customer.

Re: NetApp Usable Space Calculator

Thanks. Appreciate the feedback. I just updated the post with a new version which includes the option for 900GB SAS disks.

Re: NetApp Usable Space Calculator

Nice, thank you for this great tool!