Exam AWS Certified Solutions Architect - Associate SAA-C03 topic 1 question 146 discussion

In the Question is mentioned that it has o Demand instances...so I think is more cheapest reserved and spot

Answer is B: Reserved is cheaper than on demand the company has. And it's meet the availabilty (HA) requirement as to spot instance that can be disrupted at any time. PRICING BELOW. On-Demand: 0% There’s no commitment from you. You pay the most with this option. Reserved : 40%-60%1-year or 3-year commitment from you. You save money from that commitment. Spot 50%-90% Ridiculously inexpensive because there’s no commitment from the AWS side.

Reserved and spot instances are cheaper than on-demand ones.

couldn't decide between B and C, but C seems right. The thing with reserved instances is that you have to commit for 1 or 3 years, which is not mentioned in this use case.

Though ASG is not mentioned but it is implied. Mixing on-demand and spot is the best to save money. Reserved is expensive because you need to pay on the capacity all times.

Since Reserved Instances are cheaper than On-Demand and also Spot Instances are best suited here for additional requitements.

Ans B - Reserved guarantees baseline level operation; Spot for peaks - its stateless

B is the correct answer, using reserved instances is definitely more cost effective than using on-demand instances.

B for sure

Agree with others

This is a bit unclear, but B seems the best option of the ones given. Usage is either "heavy" (during the 8 hours), "moderate and steady" (overnight) or "low" (during weekends). So there is always SOME usage, which could be covered by a few Reserved Instances (which would be cheaper than On-Demand Instances). A - "Spot instances for the entire workload", might 'affect the availability of the application' B - Seems the best answer C - More expensive than B D - Dedicated instances aka dedicated hardware -> very expensive

I vote for C: Please explain me if I am wrong: If application experiences heavy usage during an 8-hour period each business day and all other time we don't need them? it mean than on-demand price will be only 33% from total cost so saving will be near 66%, more than reserved instances all other load we can cover by spot instances. So why it not C?

Selected Answer: C On-Demand Instances are more appropriate than Reserved Instances because "The application is used heavily for a period of 8 hours every weekday" requirements.

The answer should be C. Because if reserved is chosen, you have to pay for every hour. I calculate from this pages (if I'm wrong please correct me) https://aws.amazon.com/ec2/pricing/reserved-instances/pricing/#:~:text=Reserved%20Instances%20provide%20you%20with,instances%20when%20you%20need%20them. Example: for t4g.nano Reserved instances (0.003X24X365)+(1.90X12)=49.08 On demand instance (0.0042X8X365)=12.264 it will be added spot instances

B, since the application needs to be on 24/7 for business days; on weekends, it can be off at any moment. The question mentions something like 8 hour per business day but!!! this is just for heavy usage, the application is also on during overnight.

Why it's not A ? the application is "stateless" so it can be interrupted at any moment and the spot option is the cheaper one.

If we assume moderate usage of 8 hours on average every day a week, this should be on demand, since it is not a 24/7 server. There is downtime on the weekends and after the initial 8 hours.