Exam AWS Certified Solutions Architect - Professional SAP-C02 topic 1 question 296 discussion

I think the key here is to focus on the requirements. It is clearly stated that the requirement is that the strategy meet an RPO of 2 hours and an RTO of 4 hours. Even though option C is the most cost-effective, it is contingent on a few external factors, like the size of the data, the data change rate, etc., which cannot be assumed at the risk of breaching RPO and RTO requirements. So based on that, the most effective option is D.

Answer: C Weird question. Sometimes I think there is no BEST answer and that they were created just to confuse people. Anyway, thinking on cost and the mentioned RPO and RTO, I would still go with C (if they were longer, it would be easier to choose among the questions).

D. Near real-time replication with Aurora global database and DynamoDB global tables, easily meeting the 2-hour RPO. Quick failover capability with Route 53, meeting the 4-hour RTO. A more cost-effective solution compared to option A (no CloudFront costs) and option B (no need for custom replication setup with DMS, EventBridge, and Lambda).

AWS Backup has the lowest cost but cannot fulfill RTO requirement.

I voted for D. While option C (using AWS Backup) might seem cost-effective, it may not consistently meet RTO/RPO requirements, especially for large datasets. The reliability of AWS Backup, while generally good, cannot guarantee meeting specific recovery time and recovery point objectives. The question might be designed to trick you into choosing the cheapest option, but a reliable disaster recovery solution is crucial. Therefore, I chose option D."**

I think we need to assume the ideal situation whenever there is no specific mention about the database size. In ideal situation 2 hours is more than sufficient to take backup. Since the question has the key for cost-effectiveness, the answer would be C. In addition, there are multiple options available to expedite the recovery from backup if the normal path can't meet RTO.

Why AWS Backup (Option C) May Not Be Suitable: Cross-region snapshot copies "can take hours to complete" depending on database size and regions involved.Since the database size is unknown Cross-region copies have variable completion times. We need to guarantee an RPO of 2 hours. AWS Backup cannot reliably guarantee the 2-hour RPO requirement due to these uncertainties. Better Solution: Aurora Global Database (Option D) would be more appropriate because: It provides replication lag of typically less than 1 second, easily meeting the 2-hour RPO requirement. It enables fast global failover to secondary regions in minutes, meeting the 4-hour RTO requirement. Route 53 failover routing provides automated traffic switching during recovery. While Aurora Global Database may be more expensive than AWS Backup, it's the only solution among the options that can definitively guarantee meeting both the RPO and RTO requirements regardless of database size. Therefore, Option D is the correct choice as it's the only solution that can reliably meet both the RPO and RTO requirements with certainty.

The ONLY reason I am going with C is that AWS Backup is generally more cost-effective compared to continuous replication setups like Aurora Global Database or DynamoDB Global Tables1. It allows you to create point-in-time backups and restore them in a secondary region, meeting the RPO requirement of 2 hours and RTO requirement of 4 hours

vote for D. Global table

C for me

My answer is B. B is cheapest and it will create only when event occurs. it will complete within 2hours. C and D are costly options compare to BH

AWS often publish this kind of bad framed question. The question is looking for most cost effective solution. So I believe C is the expected answer even it is not complete answer. But C has three big problems: 1. a backup is a backup, if it doesn't provide a way to restore, it is only a backup and is not a complete DR. 2. It doesn't mention the frequency of the backup nor the continuous backup, which means we don't know whether it can meet the 2hr RPO. 3. It doesn’t mention the ECS DR. Well, neither does the other answers. . Aurora global db and DynamoDB global table are apparently more expensive. With the question design, they should be excluded even they are actually complete answers.

Github Copilot answer: The solution you proposed is a good approach for implementing a disaster recovery (DR) strategy. Here's a breakdown of how it works: 1. **AWS Database Migration Service (DMS)**: This service can be used to replicate data from your Amazon Aurora databases in the primary region to the secondary region. This ensures that you have a backup of your data in case of a disaster in the primary region. 2. **Amazon EventBridge and AWS Lambda**: These services can be used together to trigger the replication process whenever there is a change in the Aurora databases. 3. **DynamoDB Streams, EventBridge, and Lambda**: DynamoDB Streams capture table activity, and you can use Lambda functions triggered by EventBridge to process the stream and replicate the changes to DynamoDB tables in the secondary region.

We have no idea the size of the db thus we can't assume we can reach an RTO of 4 hours using backups. D is the cheapest solution out of A, B and D.

https://docs.aws.amazon.com/whitepapers/latest/disaster-recovery-workloads-on-aws/disaster-recovery-options-in-the-cloud.html Thus the correct answer is C, as the minimum RPO for AWS Backup (unless you use Point-in-time recovery) is exactly 2 hours.

Backup restore can take more than 4 hours, so D

The correct answer is in fact D. Though the question asks for a cost effective option. Option C does not guarantee on the mentioned RPO and RTO. So between A and D what is the most cost effective way. D wins as it does not have cost of Cloudfront