PAS-C01 Design of SAP Workloads on AWS Practice Question
An SAP administrator is troubleshooting a performance issue on an SAP HANA database running on an r5.24xlarge instance. The database is I/O bound during high load periods. The administrator has already verified that the EBS volumes are not saturated. What should the administrator check next?
⚠ Common exam trap
Many candidates assume EBS optimization must be manually verified or enabled, but on modern Nitro-based instances like r5, it is always active, so the real bottleneck is often the network adapter configuration.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Check the Elastic Network Adapter (ENA) settings and consider tuning the ring buffer size
On an r5.24xlarge instance, EBS optimization is always enabled by default, so verifying it again is unnecessary. The issue is I/O bound during high load, but EBS volumes are not saturated, indicating the bottleneck is likely at the network layer. The Elastic Network Adapter (ENA) ring buffer size can become overwhelmed under high network traffic, causing packet drops and increased latency, which manifests as I/O wait. Tuning the ring buffer size (e.g., using `ethtool -G eth0 rx 4096 tx 4096`) can reduce drops and improve throughput for SAP HANA's network-intensive operations.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Verify that EBS optimization is enabled
Why it's wrong here
EBS optimization is enabled by default on large instances and likely not the issue.
- ✗
Increase the SWAP space on the instance
Why it's wrong here
SAP HANA should not use SWAP; it relies on memory.
- ✗
Upgrade to a compute-optimized instance like c5.24xlarge
Why it's wrong here
Compute-optimized instances have less memory, unsuitable for HANA.
- ✓
Check the Elastic Network Adapter (ENA) settings and consider tuning the ring buffer size
Why this is correct
Tuning ENA can improve network throughput, which may be the bottleneck for I/O bound operations.
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Same concept, more angles
1 more way this is tested on PAS-C01
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. An SAP system on AWS is running on an r5.16xlarge instance. The system is experiencing network throughput bottlenecks. Which step should be taken to improve network performance?
medium- A.Move the instance to a placement group
- B.Attach an Elastic Fabric Adapter
- ✓ C.Enable Enhanced Networking and install the ENA driver
- D.Change the instance type to c5.18xlarge
Why C: Enabling Enhanced Networking and installing the Elastic Network Adapter (ENA) driver is the standard method to achieve higher packet-per-second (PPS) performance, lower latency, and increased network bandwidth on supported instance types like r5.16xlarge. Without the ENA driver, the instance uses the older Xen network driver, which cannot utilize the full 25 Gbps network bandwidth available to r5 instances, leading to throughput bottlenecks.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This PAS-C01 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the PAS-C01 exam.