Which statement is true about restoring data from incremental backups?

Which statement is true about restoring data from incremental backups?

• A. You need the last full backup and all incremental backups.
• B. You need only the most recent incremental backup.
• C. You need only the last full backup.
• D. Incremental backups cannot be used for restoration.

Answer: (A)

Incremental backups contain only the changes since the previous backup. To reconstruct the data, you start with the last full backup and then apply each incremental backup in order up to the desired recovery point. Without the full backup, there’s nothing to base the increments on, and without all the intervening incremental backups, the restored data would be incomplete. For example, if a full backup was created on Sunday and incremental backups were made on Monday, Tuesday, and Wednesday, restoring to Wednesday requires Sunday plus Monday, Tuesday, and Wednesday in that exact sequence. Relying on only the most recent incremental would miss the changes from earlier days, and relying on only the last full backup would miss all changes after that full backup. Incrementals are indeed usable for restoration, just in the required full-plus-increments combination.

Incremental backups contain only the changes since the previous backup. To reconstruct the data, you start with the last full backup and then apply each incremental backup in order up to the desired recovery point. Without the full backup, there’s nothing to base the increments on, and without all the intervening incremental backups, the restored data would be incomplete.

For example, if a full backup was created on Sunday and incremental backups were made on Monday, Tuesday, and Wednesday, restoring to Wednesday requires Sunday plus Monday, Tuesday, and Wednesday in that exact sequence. Relying on only the most recent incremental would miss the changes from earlier days, and relying on only the last full backup would miss all changes after that full backup. Incrementals are indeed usable for restoration, just in the required full-plus-increments combination.