I was looking to find all the VMFS3 datastores still existing in an environment today so that we could migrate them to their new VMFS5 counterparts. I used this PowerCLI one-liner which I thought someone else might find useful. Let me know if it helps!
[code language=”powershell”]Get-Datastore | Select Name,FileSystemVersion,CapacityGB | Where {
$_.FileSystemVersion -lt 5 -and $_.FileSystemVersion -ne $null
} | Sort Name | ft -autosize[/code]