Recipe 19.14. Caring for Backup Media


Problem

You want to take care of your backup media so that when you need to use it, it works properly.

Solution

The following are some guidelines to remember when using, handling, and storing the various backup media you use:

  • Spot-test your files periodically and transfer the data if readability problems develop. After all, a backup is no good if it can't be restored.

  • Keep your tapes boxed until you need to use them. Opening tape boxes prematurely will unnecessarily increase a new tape's exposure to dust, moisture, and sunlight, and could eventually erode a tape's quality and dependability.

  • Do not attempt to load a tape into the drive if you notice dents, cracks, or moisture in the tape's cases, hinged doors, or file-protect selectors.

  • Store your tapes at room temperature.

  • Avoid magnetic fields. Speakers, microwave ovens, and printer heads can all produce fields that can erase part or all of your backup.

  • Purchase quality disk media, be it CD-Rs, CD-RWs, or DVDs. Cheap media not to be confused with inexpensive media causes many longevity problems.

  • Don't store CDs or DVDs in soft sleeves, or stack them without protective covering. All of these actions will cause scratches of the surface of the disk, which can result in unreadable sections.

  • Limit your disks' exposure to light.

Discussion

The most reliable method of testing your existing backup media to ensure its validity is to perform a test restore of certain files at random points of the backup set. If you have a particularly critical backup, perform full test restores regularly as often as every six months to make sure the media isn't prematurely wearing out.

The lifetime ranges of certain media under standard storage conditions are things to consider when storing backup media. The following are good estimates of specific media lifespans:


Read-only CDs

5 to 100 or more years depending on disk manufacturing quality


CD-R

5 to 200 years depending on disk type and manufacturing quality


CD-RW

5 to 100 or more years depending on manufacturing quality


DVD, DVD-R, DVD-RW

Similar to that of a CD


Tapes

10 to 30 years


Diskettes and hard drives

5 to 15 years

You should also take into account the life or popularity of a specific media type's playback machine. The media may survive for 100 years, but the technology to play the media may have disappeared in that time. Replacement machines might disappear from stores before you have made the change to a new format. Remember to keep backups refreshed as technology changes.

Also consider the following: cheap mass-produced CD-R disks and similar disk media are actually worse than floppies: the quality of the media depends on the dye substrate. There are a lot of studies on this; http://www.mam-a.com is just one company selling archival quality CD-Rs. A lot of photographers use them for backups.

See Also

The Ontrack Data Protection Guide, at http://www.storagesearch.com/ontartic.html



Windows XP Cookbook
Windows XP Cookbook (Cookbooks)
ISBN: 0596007256
EAN: 2147483647
Year: 2006
Pages: 408

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