(ISC)2 Certified in Cybersecurity Practice Exam

In a scenario where Joe conducts full backups on Sunday and incremental backups during the week, what backups are needed after a failure on Friday morning?

1. Only Thursday's backup

2. Sunday's full backup and all incremental backups from Monday to Thursday

3. Only the last backup

4. Sunday's full backup and Thursday's differential backup

The correct answer is: Sunday's full backup and all incremental backups from Monday to Thursday

In this scenario, Joe's backup strategy involves performing a full backup on Sundays and incremental backups throughout the week. An incremental backup saves only the data that has changed since the last backup, which means that each incremental backup relies on the previous backup for completeness. In the event of a failure on Friday morning, recovery requires the latest full backup along with all subsequent incremental backups taken since that last full backup. Therefore, the restoration process would need: 1. The full backup from Sunday. This contains all the data as of that point in time. 2. The incremental backups from Monday, Tuesday, Wednesday, and Thursday, which contain only the changes made since the last backup (in this case, the last full backup on Sunday). Thus, the correct approach to restoring data after the failure would require all these backups in sequence. By only restoring Sunday’s full backup and all incremental backups from Monday to Thursday, all required data will be recovered to a point right before the failure occurred on Friday morning, aligning perfectly with Joe's backup schedule. Other options, such as retrieving only Thursday's backup or just the last backup, would not provide a complete recovery of data. A differential backup, which is not in Joe’s stated strategy, would also not correctly represent the