I just tried and found a builtin cmdlet:
PS H:\> Get-NaVolRoot
Name State TotalSize Used Available Dedupe FilesUsed FilesTotal Aggregate
---- ----- --------- ---- --------- ------ --------- ---------- ---------
volroot online 197,6 GB 3% 191,3 GB False 8k 7M aggr0
What version of the DataONTAP PS Toolkit are you using?
I'm on:
PS H:\> Get-Module DataOntap | fl
Name : DataOntap
Path : C:\Program Files (x86)\NetApp\Data ONTAP PowerShell Toolkit\DataOntap\DataOntap.psd1
Description : Data ONTAP PowerShell Toolkit
ModuleType : Manifest
Version : 2.4.0
NestedModules : {DataONTAP, DataONTAP.C, DataONTAP.Alias}
ExportedFunctions : Add-NaHelpInfoUri
ExportedCmdlets : {Add-NaAggr, Add-NaCifsShare, Add-NaCredential, Add-NaFpolicyExtension...}
ExportedVariables : {}
ExportedAliases : {Add-NcHostIscsiConnection, Connect-NcHostIscsiTarget, ConvertTo-NcLun, ConvertTo-NcVhd...}