CLF-C02 Cloud Technology and Services Practice Question
A company needs to implement a disaster recovery strategy where data is continuously replicated to AWS but AWS compute resources are only started during a declared disaster. Which DR strategy does this describe?
⚠ Common exam trap
It's easy for candidates to confuse 'Pilot Light' with 'Warm Standby' because both involve some pre-provisioned resources, but Pilot Light keeps compute resources minimal and inactive until failover, whereas Warm Standby runs a scaled-down but fully operational environment.
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
✓
Pilot Light
The Pilot Light strategy involves continuously replicating data to AWS (e.g., using AWS Database Migration Service or S3 replication) while keeping only a minimal core set of AWS resources (like a small EC2 instance or RDS database) running. Compute resources are not fully provisioned until a disaster is declared, at which point they are scaled up to handle production traffic. This matches the description of data being continuously replicated but compute only started during a declared disaster.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Backup and Restore
Why it's wrong here
Backup and Restore focuses on copying data (e.g., to Amazon S3 or S3 Glacier) at scheduled intervals without any running infrastructure in AWS. When a disaster strikes, you must provision all compute resources, install software, restore data, and reconfigure networks—a process that can take hours or even days, yielding the highest RTO. Its low cost comes from paying only for storage, but the RPO is defined by the backup frequency, meaning you can lose up to the last scheduled backup's data.
- ✓
Pilot Light
Why this is correct
Pilot Light keeps just the critical data layer (like a replicated database) running continuously in AWS, along with pre-loaded AMIs and configuration scripts for the remaining application components. The compute resources are not active, so you pay for the small always-on footprint, but when a disaster is declared you quickly launch the pre-configured EC2 instances to scale up to production. This balances cost and RTO, typically achieving recovery in about ten minutes to a few hours, making it a middle-ground DR strategy.
- ✗
Warm Standby
Why it's wrong here
Warm Standby maintains a scaled-down but fully functional copy of your entire production environment running in AWS at all times, including application servers and database. Because the environment is already operational, failover only requires increasing capacity (e.g., applying Auto Scaling policies) and switching traffic, giving a lower RTO than Pilot Light, often in minutes. This continuous operation makes it more expensive than Pilot Light—you pay for the running compute even while idle—but less costly than full Multi-Site Active/Active.
- ✗
Multi-Site Active/Active
Why it's wrong here
This strategy runs full production capacity in AWS and on-premises simultaneously, typically synchronously replicating data and load-balancing live traffic across both environments. It offers near-zero RTO because failover is a simple DNS or routing change, with no provisioning or startup delays. However, it is the most expensive option on the DR spectrum, as you maintain duplicate infrastructure and continuous data synchronization, effectively paying double for idle capacity.
Quick reference
AWS S3 Storage Class Comparison
| Storage Class | Min Duration | Retrieval | Use Case |
|---|---|---|---|
| S3 Standard | None | Immediate | Frequently accessed data |
| S3 Standard-IA | 30 days | Immediate | Infrequent access, rapid retrieval |
| S3 One Zone-IA | 30 days | Immediate | Non-critical infrequent data |
| S3 Intelligent-Tiering | None | Immediate–hours | Unknown or changing access patterns |
| S3 Glacier Instant | 90 days | Milliseconds | Archive with instant retrieval |
| S3 Glacier Flexible | 90 days | Minutes–hours | Archive, flexible retrieval |
| S3 Glacier Deep Archive | 180 days | Hours | Long-term compliance archive |
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This CLF-C02 practice question is part of Courseiva's free Amazon Web Services 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 CLF-C02 exam.