hardMultiple ChoiceObjective-mapped
Database Backup Strategy for Recovery Time and Point Objectives
A large enterprise is implementing a backup strategy for a critical database that requires an RTO of 2 hours and an RPO of 15 minutes. The database is 2 TB in size. Which backup method would BEST meet these requirements while minimizing storage costs?
Quick Answer
The correct answer is weekly full backups with transactional log backups every 15 minutes. This method meets the 15-minute RPO by capturing every database change in the transaction log at that exact interval, while the weekly full backup provides a clean restore base; together, they allow recovery to any point within 15 minutes without the storage overhead of daily full backups. On the CISA exam, this question tests your understanding of balancing RTO and RPO with storage efficiency—a common trap is choosing daily full backups, which waste storage and fail to meet a tight RPO, or assuming log backups alone suffice without a full backup foundation. Remember the mnemonic: “Full for foundation, logs for loss”—the full backup anchors the restore, and frequent logs keep data loss under 15 minutes.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Weekly full backups with transactional log backups every 15 minutes
The best choice because weekly full backups with transactional log backups every 15 minutes meet the 15-minute RPO while minimizing storage costs compared to more frequent full backups. Transactional log backups are small and frequent, allowing point-in-time recovery within the RPO. The weekly full backup ensures that the RTO of 2 hours can be met by restoring the full backup and applying the log backups. Option A (daily full) would require more storage and may not meet the RPO if the last backup is older than 15 minutes. Option B (CDP) is expensive and may exceed the RTO due to complexity. Option D (daily full + differential every 4 hours) does not achieve the 15-minute RPO.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Daily full backups
Why it's wrong here
Full backups only provide a recovery point of up to 24 hours, exceeding the 15-minute RPO.
- ✗
Continuous data protection (CDP) replicating to a remote site
Why it's wrong here
CDP can meet RPO but typically requires more storage and replication bandwidth; it is often more expensive.
- ✓
Weekly full backups with transactional log backups every 15 minutes
Why this is correct
Log backups capture every transaction, achieving a 15-minute RPO, and storage cost is low compared to frequent full backups.
- ✗
A daily full backup and a differential backup every 4 hours
Why it's wrong here
Differential backups accumulate, and a 4-hour frequency does not achieve 15-minute RPO.
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Same concept, more angles
2 more ways this is tested on CISA
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A company is designing its backup strategy for a critical database that must be available 24/7. The database experiences high transaction volumes. Which backup method minimizes data loss while allowing continuous operations?
easy- A.Offline full backup performed weekly
- B.Differential backup performed daily
- ✓ C.Online backup with transaction log backups
- D.Full backup performed during low-usage periods
Why C: Online backup with transaction log backups (Option C) is correct because it allows the database to remain fully operational (24/7 availability) while capturing every committed transaction in the transaction log. In the event of a failure, you can restore the most recent full backup and then apply all subsequent transaction log backups to recover to the exact point of failure, minimizing data loss to only uncommitted transactions.
Variation 2. An organization is implementing a backup strategy for its critical database. The database is updated continuously during business hours, and the recovery point objective (RPO) is 15 minutes. Which backup method should be used to meet the RPO while minimizing backup storage and performance impact?
medium- A.Perform full backups every 24 hours
- B.Implement synchronous replication to a standby server
- ✓ C.Perform incremental backups with transaction log backups every 15 minutes
- D.Perform differential backups every 6 hours
Why C: Incremental backups with transaction log backups every 15 minutes meets the 15-minute RPO by capturing all changes since the last full or incremental backup, while transaction log backups record every individual database transaction. This method minimizes storage by only backing up changes and reduces performance impact compared to continuous replication, as log backups are lightweight and can be scheduled without constant I/O overhead.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This CISA practice question is part of Courseiva's free ISACA certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the CISA exam.