A method for tracking resizing and recreation of volumes in a block-based snapshot backup program. In an embodiment, a record ID is associated with a major and minor number assigned to each volume to be backed up. The record ID maintains a unique reference to the bitmap corresponding to a backed up volume in case the minor number is reused by the volume manager driver during a recreate operation. The length of the volume to be maintained is maintained and compared to the length of the to track any resizing of the volume by the volume manager. In the event of any resizing or recreation, the original bitmap can be replaced with an updated bitmap to ensure proper backup of the resized or recreated volumes.