Which type of backup is suitable for a construction company focusing on minimal recovery time and reasonable backup size?

• A. Full backup
• B. Incremental backup
• C. Differential backup
• D. Mirroring backup

Answer: (C)

In the context of minimizing recovery time while also considering reasonable backup size, a differential backup is particularly beneficial. This type of backup captures all the changes made since the last full backup, which means that in the event of a recovery, only the latest full backup and the most recent differential backup need to be restored.

This approach balances the need for quick recovery—since only two backup sets are required for a full restoration—and a more efficient use of storage space than a full backup, which captures all data every time it's performed.

The other methods would not provide the same efficiency in terms of recovery time and storage needs. A full backup, while providing a complete snapshot, can be very large and take a significant amount of time to perform and restore. Incremental backups, while they save space, require multiple backup sets to be restored for recovery, leading to longer recovery times. Mirroring backups provide real-time copies of data, which can consume substantial resources and may not be practical for the company's focus on reasonable backup sizes.

Thus, for a construction company needing both swift recovery and manageable backup sizes, the differential backup is the most suitable option.