By default Cinder volumes are unpartitioned, you can partition a new volume very easily in PowerShell:
$d = Get-Disk | where {$_.OperationalStatus -eq "Offline" -and $_.PartitionStyle -eq 'raw'}
$d | Set-Disk -IsOffline $false
$d | Initialize-Disk -PartitionStyle MBR
$p = $d | New-Partition -UseMaximumSize -DriveLetter "E"
$p | Format-Volume -FileSystem NTFS -NewFileSystemLabel "Volume1" -Confirm:$false
This script puts the disk online, initializes it, creates a partition and formats the volume, assigning the letter "E" and label "volume1"
Use -AssignDriveLetter if you prefer to get the first available letter.
Note: we're planning to add this feature to Cloudbase-Init, so that volumes get automatically initialized on boot.
Alessandro