It would at first appear easy to determine how big your NetApp volume is in PowerShell. There is a cmdlet called Get-NAVol and it has a property called TotalSize. Easy, right?
There is another cmdlet called Get-NAVolSize. What is the difference between the results returned by the two comdlets? Get-NAVol will show you the total size without the snap reserve space. Get-NAVolSize returns the actual size of the volume, including the snap reserve. This isn’t well documented in the Get-Help for these cmdlets and took some experimentation for me to figure out.
Hopefully this helps anyone who is confused about finding different values in the two commands.