Aurora Global Database Warm Standby for Lowest DR RTO

SAA-C03 By islever Editorial Last updated

Design highly available and/or fault-tolerant architectures.

Short answer

B Use an Aurora global database with a warm standby deployment so the DR Region has current data and an already-running, reduced-capacity stack for the lowest RTO.

Question

A rapidly growing ecommerce company is running its workloads in a single AWS Region. A solutions architect must create a disaster recovery (DR) strategy that includes a different AWS Region. The company wants its database to be up to date in the DR Region with the least possible latency. The remaining infrastructure in the DR Region needs to run at reduced capacity and must be able to scale up if necessary.
Which solution will meet these requirements with the LOWEST recovery time objective (RTO)?
  1. Use an Amazon Aurora global database with a pilot light deployment.
  2. Use an Amazon Aurora global database with a warm standby deployment. Correct Answer
  3. Use an Amazon RDS Multi-AZ DB instance with a pilot light deployment.
  4. Use an Amazon RDS Multi-AZ DB instance with a warm standby deployment.

Key Takeaways

The question tests the pilot light versus warm standby boundary inside a cross-Region Aurora DR design, and the main trap is choosing RDS Multi-AZ even though it stays within one Region.

This SAA-C03 disaster recovery question compares Aurora global database pilot light and warm standby deployments against RDS Multi-AZ. The lowest-RTO cross-Region solution is an Aurora global database with a warm standby deployment (B).

Common mistake: A is the plausible near-miss: Aurora global database is the right cross-Region service, but pilot light still needs start-up or provisioning before serving traffic, so it cannot match warm standby’s lower RTO.

Expert Analysis

Two boundaries in one question

The scenario first asks for a cross-Region DR design, so eliminate any “Multi-AZ” option. Amazon RDS Multi-AZ keeps a standby in another Availability Zone of the same Region; it does not create a database copy in a different Region. That removes C and D before RTO is compared. Amazon Aurora global database is the cross-Region database mechanism here, replicating storage to secondary Regions with low latency and keeping the DR copy current.

Pilot light vs warm standby

The remaining decision is deployment posture. The comments capture the boundary well: pilot light keeps core data and replication services running but requires additional action before it can process requests; warm standby keeps a scaled-down but fully functional copy of production that can handle traffic at reduced capacity immediately. The requirement that the remaining infrastructure “run at reduced capacity and must be able to scale up if necessary” is the warm standby definition, not pilot light.

Lowest RTO

Because warm standby already has the application tier, load balancing, and other components running in the DR Region, failover is mainly traffic cutover and scale-up. Pilot light must first start or provision capacity, which adds recovery time. Therefore B is correct: an Aurora global database with a warm standby deployment gives the lowest RTO, while A is the near-miss and C and D are not cross-Region DR at all.

Official Reference

These links open the official vendor documentation in a new tab.

Exam Strategy

When a DR question asks for the LOWEST RTO, first identify whether the options provide cross-Region replication: Multi-AZ is always same-Region, so eliminate those. Then rank deployment strategies by how much work remains at failover—active-active best, warm standby next, pilot light after that, backup/restore worst—and match the scenario’s “reduced capacity” wording to warm standby. This avoids being distracted by the database engine and focuses on the RTO ladder.

Frequently Asked Questions

Why is RDS Multi-AZ not correct for this cross-Region DR requirement?

RDS Multi-AZ places a standby in another Availability Zone within the same Region; it does not create a secondary database in a different Region. The question explicitly needs DR in another AWS Region.

Does Aurora global database with pilot light have a lower RTO than warm standby?

No. Both replicate data cross-Region, but pilot light requires additional provisioning or startup before serving traffic, while warm standby already runs a scaled-down full stack, so warm standby provides the lower RTO.

What does “reduced capacity” indicate in this DR scenario?

It points to warm standby: a fully functional but scaled-down copy of production in the DR Region that can take traffic immediately and scale up after failover.

More SAA-C03 FAQ →

Discussion 11 contributions

Compiled from public community threads and reader submissions, lightly edited for clarity. Handles and vote tallies are shown as recorded, and comments reflect the views of individual contributors.

From public community threads 11

  1. Yechi 👍 28 Answered B
    Note: The difference between pilot light and warm standby can sometimes be difficult to understand. Both include an environment in your DR Region with copies of your primary Region assets. The distinction is that pilot light cannot process requests without additional action taken first, whereas warm standby can handle traffic (at reduced capacity levels) immediately. The pilot light approach requires you to “turn on” servers, possibly deploy additional (non-core) infrastructure, and scale up, whereas warm standby only requires you to scale up (everything is already deployed and running). Use your RTO and RPO needs to help you choose between these approaches. https://docs.aws.amazon.com/whitepapers/latest/disaster-recovery-workloads-on-aws/disaster-recovery-options-in-the-cloud.html
  2. nickolaj 👍 23 Answered B
    Option A is incorrect because while Amazon Aurora global database is a good solution for disaster recovery, pilot light deployment provides only a minimalistic setup and would require manual intervention to make the DR Region fully operational, which increases the recovery time. Option B is a better choice than Option A as it provides a warm standby deployment, which is an automated and more scalable setup than pilot light deployment. In this setup, the database is replicated to the DR Region, and the standby instance can be brought up quickly in case of a disaster. Option C is incorrect because Multi-AZ DB instances provide high availability, not disaster recovery. Option D is a good choice for high availability, but it does not meet the requirement for DR in a different region with the least possible latency.
  3. leoattf 👍 10
    No, my friend. The question asks for deployment in another Region. Hence, it cannot be C or D. The answer is B because is Global (different regions) and Ward Standby has faster RTO than Pilot Light.
  4. pentium75 👍 4 Answered B
    "Different Region" rules out C and D ("Multi-AZ" is within a region) "Run at reduced capacity" = warm standby (while "pilot light" means that DR resources are shut down and are started manually in case of failover)
  5. TariqKipkemei 👍 3 Answered B
    The warm standby approach involves ensuring that there is a scaled down, but fully functional, copy of your production environment in another Region. With the pilot light approach, you replicate your data from one Region to another and provision a copy of your core workload infrastructure. Resources required to support data replication and backup, such as databases and object storage, are always on. Other elements, such as application servers, are loaded with application code and configurations, but are "switched off".
Show 6 more comments
  1. pentium75 👍 3
    "Multi-AZ" = multiple AZs in same region, but requirement is "a different AWS Region".
  2. A1975 👍 2 Answered B
    In a Pilot Light scenario, only an EC2 Instance and a DB may be running. In Warm Standby, however, everything is running — in a much smaller capacity. This means the load balancer, gateways, databases, all subnets, and everything else are ready to go on a moment's notice. with reference to below statement Option B is a better choice than Option A. "The remaining infrastructure in the DR Region needs to run at reduced capacity and must be able to scale up if necessary".
  3. Guru4Cloud 👍 2 Answered B
    An Amazon Aurora global database with a warm standby deployment provides continuous replication from one AWS Region to another, keeping the DR database up-to-date with minimal latency.
  4. awsgeek75 👍 2 Answered B
    B: Warm Standby is better when it comes to LOWEST RTO. https://docs.aws.amazon.com/whitepapers/latest/disaster-recovery-workloads-on-aws/disaster-recovery-options-in-the-cloud.html
  5. krisfromtw 👍 2 Answered D
    should be D.
  6. FajarYNC 👍 1 Answered B
    Note: The difference between pilot light and warm standby can sometimes be difficult to understand. Both include an environment in your DR Region with copies of your primary Region assets. The distinction is that pilot light cannot process requests without additional action taken first, whereas warm standby can handle traffic (at reduced capacity levels) immediately. The pilot light approach requires you to “turn on” servers, possibly deploy additional (non-core) infrastructure, and scale up, whereas warm standby only requires you to scale up (everything is already deployed and running). Use your RTO and RPO needs to help you choose between these approaches.

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