Normal, Incremental, Differential? Getting Backups Right

The Windows Backup utility supports a number of different backup types that help to make backups less time consuming, but its important to understand how they work. By using a combination of Normal and then Incremental or Differential backups, creating your own backup strategy will get data backed up both efficiently and effectively.

A Normal backup will back up all selected files and folders, and clear their archive attribute to mark them as having been backed up. An Incremental backup of the same selected files and folders will only back up those that have changed since the last Normal or Incremental backup (those that have their archive attribute set), and then clear the archive attribute. An Incremental backup will back up all selected files and folders that have changed since the last Normal or Differential backup, but will not change the archive attribute. Although the impact on the archive attribute seems trivial, it impacts how data is backed up.

A combination of Normal and Incremental or Differential backups can make backing up your files a breeze. For example, if you create a Normal backup on Monday, all selected files will be backed up. If you then performed a Differential backup Tuesday through Friday, each of these backups would include all files that have changed since Monday. As such, if you needed to restore data on Saturday, you would only need to restore the original Normal backup, and the last available Differential backup. If the same strategy started with a Normal backup on Monday and then Incremental backups every other day, a restore on Saturday would require the Normal backup and then each Incremental backup since to fully restore files. The moral of the story? Incremental backups take less time to create, but involve a longer restore process. The best bet for most users is Normal plus Differential – the backups take a tiny bit longer, but restoration is a simpler process.

Author: Dan DiNicolo

Dan DiNicolo is a freelance author, consultant, trainer, and the managing editor of 2000Trainers.com. He is the author of the CCNA Study Guide found on this site, as well as many books including the PC Magazine titles Windows XP Security Solutions and Windows Vista Security Solutions. Click here to contact Dan.