The answer is KMS throttling due to exceeded API request rate limits. When you encrypt an EBS volume with AWS KMS, every I/O operation to the volume requires a Decrypt API call to the KMS service to unwrap the encrypted data key. For a high-throughput SAP HANA database, this can easily surpass the default KMS symmetric key rate limit of 5,500 requests per second per Region, causing throttling and increased latency that manifests as database slowness. On the AWS Certified SAP on AWS Specialty PAS-C01 exam, this question tests your understanding of how KMS throttling impacts encrypted EBS for SAP HANA, often appearing as a trap where candidates blame network or instance limits instead. The key insight is that encryption adds a synchronous KMS dependency to every disk read, so a sudden performance drop after enabling encryption points directly to KMS throttling. Memory tip: think “KMS = Key Management Slowdown” for encrypted HANA workloads.
PAS-C01 Design of SAP Workloads on AWS Practice Question
This PAS-C01 practice question tests your understanding of design of sap workloads on aws. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
An SAP customer is using AWS KMS to encrypt EBS volumes for an SAP HANA database. The database administrator reports that the database is slow after enabling encryption. What is the MOST likely cause?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The KMS API request rate limit is being exceeded, causing throttling.
When EBS volumes are encrypted, every I/O operation to the volume must call AWS KMS to decrypt the data key. If the database workload generates a high rate of these requests, it can exceed the KMS API request rate limit (default 5,500 requests per second per Region for symmetric keys), causing throttling and increased latency. This is the most likely cause of the observed slowdown after enabling encryption.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
The KMS key is not rotated frequently enough.
Why it's wrong here
Key rotation does not affect performance.
✓
The KMS API request rate limit is being exceeded, causing throttling.
Why this is correct
High request rate can cause throttling and delays.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
The EBS volume is not using the correct instance type for encrypted volumes.
Why it's wrong here
All instance types support encrypted volumes.
✗
The KMS key is using a symmetric algorithm that degrades CPU performance.
Why it's wrong here
KMS encryption uses hardware acceleration, not CPU.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often attribute performance degradation to CPU overhead from encryption algorithms, but AWS KMS throttling is the real bottleneck because EBS encryption relies on API calls for key decryption, not on-instance cryptographic processing.
Detailed technical explanation
How to think about this question
EBS encryption uses an envelope encryption model: a unique data key (DK) is generated by KMS and used for AES-256 encryption of the volume at the hypervisor level. Each time an encrypted EBS volume is attached or accessed, the instance must call KMS to decrypt the DK, and subsequent I/O operations may require re-decryption if the DK is not cached. KMS throttles at 5,500 requests per second per Region for symmetric keys (adjustable via Service Quotas), and exceeding this rate causes `ThrottlingException` errors that manifest as increased latency in database operations. In practice, SAP HANA workloads with high IOPS can easily hit this limit if multiple volumes or frequent re-attachments are involved.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A cloud solutions architect for a retail company is evaluating services for a new workload. The correct answer here reflects best practice for the specific scenario described — not a general cloud recommendation. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Cloud exam questions reward reading the constraint carefully: the same technology can be right or wrong depending on the use case.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Design of SAP Workloads on AWS — This question tests Design of SAP Workloads on AWS — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The KMS API request rate limit is being exceeded, causing throttling. — When EBS volumes are encrypted, every I/O operation to the volume must call AWS KMS to decrypt the data key. If the database workload generates a high rate of these requests, it can exceed the KMS API request rate limit (default 5,500 requests per second per Region for symmetric keys), causing throttling and increased latency. This is the most likely cause of the observed slowdown after enabling encryption.
What should I do if I get this PAS-C01 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Question Discussion
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