Which statement describes the 3-2-1 backup rule?

Which statement describes the 3-2-1 backup rule?

• A. Keep four copies on one medium
• B. Keep at least three copies of data on two different media with one off-site
• C. Only keep one copy off-site
• D. Keep two copies on the same drive

Answer: (B)

The 3-2-1 backup rule means you should have three copies of your data, stored on two different types of storage media, with one copy kept off-site. This setup protects you from different failure modes: one copy is the original, one is a local backup on a separate medium, and the off-site copy guards against local disasters like theft, fire, or flood. For example, keep your data on your computer, have a backup on an external drive, and another backup in cloud storage or at a different location. The diversity of media reduces the chance that a single failure wipes out all copies, and the off-site copy ensures recovery even if something happens to your primary workspace. The other options don’t meet this balance: having all copies on the same medium offers no protection against media failure; keeping only one off-site copy ignores local risks; and two copies on the same drive provide no redundancy if that drive fails.

The 3-2-1 backup rule means you should have three copies of your data, stored on two different types of storage media, with one copy kept off-site. This setup protects you from different failure modes: one copy is the original, one is a local backup on a separate medium, and the off-site copy guards against local disasters like theft, fire, or flood. For example, keep your data on your computer, have a backup on an external drive, and another backup in cloud storage or at a different location. The diversity of media reduces the chance that a single failure wipes out all copies, and the off-site copy ensures recovery even if something happens to your primary workspace. The other options don’t meet this balance: having all copies on the same medium offers no protection against media failure; keeping only one off-site copy ignores local risks; and two copies on the same drive provide no redundancy if that drive fails.