I had a question come through twitter the other day from @AleXgTorres around how one would check a cluster's datastores for VAAI compatability.  First of all why is this important?  Typically to check VAAI compatability one goes to the Configuration -> Storage and looks at the table of datastores which lists whether VAAI is Supported/Unsupported/Unknown.  The important part of this is that all ESX hosts decide for themselves whether a datastore is VAAI capable.  Since this is a fan-out situation, a little scripting can help to gather the data to see which hosts have identified VAAI capabilities (Supported/Unsupported) and which ones have yet to send a VAAI test command (Unknown).

[array]$arrVMHost = Get-VMHost

$arrVMHost | %{ 

        $VMHost = $_

        $configStorageSystem = Get-View (Get-View $VMHost.ID).ConfigManager.StorageSystem

        [array]$arrVolumeMountInfo = $configStorageSystem.FileSystemVolumeInfo.MountInfo

        $arrVolumeMountInfo | select @{n="VMHostName";e={$VMHost.name}},@{n="name";e={$_.Volume.Name}},@{n="VAAISupport";e={$_.VStorageSupport}}

} | sort name,VMHostName

That's it! The first line can be modified to first specify a cluster (get-cluster name | get-vmhost) if you want to be more granular than collecting all ESX hosts from the vCenter instance you are using through PowerCLI.