CompTIA A+ Core 2 (220-1202)Operational ProceduresMedium
A company performs a full backup every Sunday night and a differential backup every other night of the week. On Thursday morning, the server crashes and must be restored to its most recent state. Which backups are needed to complete the restore?
- AOnly the Sunday full backup
- BThe Sunday full backup and the Wednesday night differential backup
- COnly the Wednesday night differential backup
- DThe Sunday full backup plus the Monday, Tuesday, and Wednesday differential backups
Show answer & explanationAnswer & explanation
Correct answer: B. The Sunday full backup and the Wednesday night differential backup
A differential backup captures all changes made since the last full backup, so only the most recent differential (Wednesday) plus the original full backup (Sunday) are needed. Unlike incremental backups, differentials don't need to be chained together in sequence.
Why the other options are wrong
- A. This would omit all changes made after Sunday.
- C. The differential alone cannot restore data existing before the last full backup.
- D. This describes incremental backup restore logic, not differential.
Differential Backup Restore
A differential backup stores all changes since the last full backup, so restoring requires only the full backup plus the most recent differential.
- Differential backups grow larger each day until next full backup
- Only two backups needed to restore: full + latest differential
- Faster restore than incremental but larger storage use over time
Memory trick: Differential = 'Different from full, but always compares to full.'