How can I determine what cluster size SnapDrive for Windows will use when formatting an NTFS file system on a NetApp virtual disk or Logical Unit (LUN)? SnapDrive only formats using Microsoft NTFS and...How can I determine what cluster size SnapDrive for Windows will use when formatting an NTFS file system on a NetApp virtual disk or Logical Unit (LUN)? SnapDrive only formats using Microsoft NTFS and it utilizes the default format cluster size that is used by Windows Disk Management. The following table describes the default NTFS cluster sizes for Windows Server 2003 file system volumes: Windows Disk MGMT does this and it chooses the default for the size of the virtual disk.