Exam AWS Certified Solutions Architect - Professional SAP-C02 topic 1 question 136 discussion

C correct DocumentDB only have on-demand instance but not on-demand capacity mode, the mode is for DynamoDB

A = Aurora supports MySQL and PostgreSQL, not MongoDB. App changes are not allowed B = This could work but DocumentDB provides managed MongoDB instance that is preferable C = correct D = there isn't on-demand capacity mode, in 2022 launched MondoDB Elastic Cluster that eliminates the need to choose, manage or upgrade instances and allows to scale up to 4PiB storage whereas instance based scales up to 128TiB. I thing this question is pre elastic cluster as this is ambiguous between C and D

C: DocumentDB has an on-demand instance type but NO on-demand capacity mode. Note the difference between the two: On-demand instance type is specific to EC2 pricing for hourly or per-second compute capacity. On-demand capacity mode is specific for DynamoDB and Kinese for pay-per-request pricing and no up-front capacity planning.

D is the correct answer https://aws.amazon.com/documentdb/pricing/ on-demand instance is supported by DocumentDB

C, documented. No exists the on-demand capacity mode

'Appropriately sized instances' Means on-demand ? that is quite vague..

DocumentDB does indeed support on-demand capacity mode (Contrary to what other users say here) https://aws.amazon.com/blogs/database/running-spiky-workloads-and-optimizing-costs-by-more-than-90-using-amazon-dynamodb-on-demand-capacity-mode/ On-Demand is ideally to a use case where you have unpredictable or variable database workloads, like this case, it is not said anywhere the expected workload, so it is better to start with On-demand , and later when you know the workload you can cahnge it.

There is no on-demand capacity mode for DocumentDB, though there is on-demand vCPU based pricing available.

Amazon DocumentDB does NOT have on-demand capacity mode, so its option C.

I was leaning towards Option C but "Appropriately sized instances" is vague since the question does not state the size of Mongo DB. On-demand instances serve the purpose here, they are offered by DocumentDB, see the link https://aws.amazon.com/documentdb/pricing/

its a c

c-c-c-c-c-c-c-c On-demand capacity mode as suggested in D may not provide the same level of high availability as multi-Availability Zone deployments. So it's c-c-c-c-c-c-c for me.

See best practices for amazon documentdb - instance sizing in docs. Addicionally there is no on-demand capacity mode.

DocumentDB does indeed support on-demand capacity mode (Contrary to what other users say here) https://aws.amazon.com/blogs/database/running-spiky-workloads-and-optimizing-costs-by-more-than-90-using-amazon-dynamodb-on-demand-capacity-mode/ but this mode is good for spikey workloads and does not address the high availablity requirement

See best practices for amazon documentdb - instance sizing in docs.

Going wit C. I still call the DocumentDB used in mode C "on-demand mode" because you have to select the Ec2 instance; the pricing documentation still uses that name. There is an Elastic cluster for DocumentDB. Could it be that option D "on-demand capacity mode" is referring to Elastic mode?

Amazon DocumentDB does not support an on-demand capacity mode. You can only choose from different instance classes that have fixed compute and memory resources. However, you can scale your instances up or down as needed, and you can also pause and resume your instances to save costs. Amazon DocumentDB also automatically scales your storage and I/O based on your data size and workload.