All storage media, whether hard drives, discs or data tapes, will wear out over time, rendering your data files inaccessible. To ensure ongoing access to both your active data files and your data archives, it is important to continually monitor the condition of your storage media and track its age. Older storage media and media that show signs of wear should be replaced immediately. Use the following guidelines to ensure the ongoing integrity and accessibility of your data:
- Test Your Storage Media Regularly: As noted in the “Backup Your Data” best practice, it is important to routinely perform test retrievals or restorations of data you are storing for extended periods on hard drives, discs or tapes. It is recommended that storage media that is used infrequently be tested at least once a year to ensure the data is accessible.
- Beware of Early Hardware Failures: A certain percentage of storage media will fail early due to manufacturing defects. In particular, hard drives, thumb drives and data tapes that have electronic or moving parts can be susceptible to early failure. When putting a new drive or tape into service, it is advisable to maintain a redundant copy of your data for 30 days until the new device “settles in.”
- Determine the Life of Your Hard Drives: When purchasing a new drive unit, note the Mean Time Between Failure (MTBF) of the device, which should be listed on its specifications sheet (device specifications are usually packaged with the unit, or available online). The MTBF is expressed in the number of hours on average that a device can be used before it is expected to fail. Use the MTBF to calculate how long the device can be used before it needs to be replaced, and note that date on your calendar (For example, if the MTBF of a new hard drive is 2,500 hours and you anticipate having the unit powered on for 8 hours a day during the work week, the device should last about 2 years before it needs to be replaced).
- Routinely Inspect and Replace Data Discs: Contemporary CD and DVD discs are generally robust storage media that will fail more often from mishandling and improper storage than from deterioration. However lower quality discs can suffer from delamination (separation of the disc layers) or oxidation. It is advisable to inspect discs every year to detect early signs of wear. Immediately copy the data off of discs that appear to be warping or discolored. Data tapes are susceptible both to physical wear and poor environmental storage conditions. In general, it is advisable to move data stored on discs and tapes to new media every 2-5 years (specific estimates on media longevity are available on the web).
- Handle and Store Your Media With Care: All storage media types are susceptible to damage from dust and dirt exposure, temperature extremes, exposure to intense light, water penetration (more so for tapes and drives than discs), and physical shock. To help prolong its operational life, store your media in a dry environment with a comfortable and stable room temperature. Encapsulate all media in plastic during transportation. Provide cases or plastic sheaths for discs, and avoid handling them excessively.
Successful preservation depends in great part on storage media that are in good physical and operational condition.
"Longevity: How Long Do CDs/DVDs/Tapes Last?" DigitalFAQ.com. Last updated April, 2008.
"Reliability and Availability Basics." EventHelix.com. Accessed 2011-05-11.