Exam AWS Certified Solutions Architect - Professional topic 1 question 438 discussion

I do support Answer "C". File gateway is limited by performance its gateway instance, whether EC2 or On-premises, Cache will get filled up fast if not properly configured, For large number of EC2 instances EFS scales better. So, bottom line is File Storage gateway is for legacy applications and you have to add cost of large gateway instances before comparing it to same quantity of EFS storage. https://www.reddit.com/r/aws/comments/82pyop/storage_gateway_vs_efs/

B This ensures the content stays on-premise but of cause sacrifice the fact that the EC2 will be accessing slight stale data via the S3 bucket because there is a replication time lag. Key is “without delaying the content refresh process”. I assume the content is on premise and the important fact is EFS is private only, it cannot be exposed to public and hence how would EFS be able to update from those “sources”? A\C\D: This will delay the content refresh process. Because of the propagation delay tied to data traveling over long distances, the network latency of an AWS Direct Connect connection between your on-premises data center and your Amazon VPC can be tens of milliseconds. If your file operations are serialized, the latency of the AWS Direct Connect connection directly impacts your read and write throughput. In essence, the volume of data you can read or write during a period of time is bounded by the amount of time it takes for each read and write operation to complete. https://docs.aws.amazon.com/efs/latest/ug/performance-onpremises.html

The correct answer is B. This solution meets all of the requirements: It allows the company to scale the web infrastructure up and down in response to load. It keeps the content refresh process running without delay. It is secure and reliable. The other solutions are not as effective. Solution A would require the company to synchronize the content between the NAS server and the Amazon EBS volume on a regular basis. This could delay the content refresh process. Solution C would require the company to expose an Amazon EFS share to on-premises users. This could pose a security risk. Solution D would require the company to update the web server instances from the NAS server on a nightly basis. This could delay the content refresh process.

https://docs.aws.amazon.com/efs/latest/ug/efs-onpremises.html

vote for B

Storage gateway can store data in S3 , Glacier or EBS. So the answer is B. Ref: https://aws.amazon.com/blogs/storage/cloud-storage-in-minutes-with-aws-storage-gateway/

Ans: C

C's problem is without mentioning how the data transition/migration. B does mention "replicate content to AWS". Question asked "transition its online infrastructure to AWS without causing a delay in the process of content refreshment". So Storage Gateway is way to go as my understanding.

Answer is C

C. Expose an Amazon EFS share to on-premises users to serve as the NAS serve. Mount the same EFS share to the web server Amazon EC2 instances to serve the content.

C is right

I'd go with C. with DX EFS can be accessed from on premises

It's C

Answer is C Why not B? EFS will reflect the changes to files immediately during the day as opposed to File Gateway which could be slower. EFS will also scale up/down nicely. There no cost restriction in the question.

Looking at the question , it says a Centralized File share to multiple web servers. EFS does this

C Correct

Important phrase in the question "without delaying the content refresh process". But the phrase "scale resources up and down in response to load" kind of tricks to forcefully think for ELB & Auto scaling. The actual point is to refresh the content without delay you need a shared file server mount point for both On-prem and AWS. which EFS can prove. Correct Answer is C