PAS-C01 Design of SAP Workloads on AWS Practice Question
An SAP system is experiencing performance issues during peak hours. The SAP application servers are running on EC2 instances behind a Network Load Balancer (NLB). The NLB is configured to use cross-zone load balancing. The issue is that one application server receives significantly more traffic than others. What is the most likely cause?
⚠ Common exam trap
It's easy for candidates to assume cross-zone load balancing alone ensures even distribution, but they overlook that the NLB's flow hash algorithm inherently causes per-flow stickiness, which can lead to imbalance when a small number of clients generate many flows.
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
✓
The flow hash algorithm is causing an uneven distribution of client traffic
The Network Load Balancer (NLB) uses a flow hash algorithm based on the 5-tuple (source IP, source port, destination IP, destination port, and protocol) to route traffic. This algorithm is designed to maintain session stickiness, but it can cause uneven distribution if a small number of clients generate a disproportionate amount of traffic, as each client's flows are consistently sent to the same target. Cross-zone load balancing distributes traffic across all targets in all enabled Availability Zones, but it does not alter the flow hash algorithm's per-flow routing, so one server can still receive more flows if its hash bucket is overloaded.
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 application servers have different instance sizes, causing the NLB to send more traffic to larger instances
Why it's wrong here
NLB does not consider instance size for traffic distribution.
- ✗
The NLB is using round-robin algorithm and one server is slower
Why it's wrong here
NLB uses a flow hash algorithm, not round-robin.
- ✓
The flow hash algorithm is causing an uneven distribution of client traffic
Why this is correct
NLB uses a flow hash based on source IP, port, and protocol; with few clients, distribution can be uneven.
- ✗
The health check is failing on the other servers
Why it's wrong here
If health check fails, those servers would be removed from rotation; they are receiving less traffic, not more.
Go deeper
Related to this question
About these practice questions
This PAS-C01 question is part of Courseiva's 1,616-question bank — original exam-style content with full explanations and wrong-answer analysis, never real exam questions or exam dumps. Learn why practice questions differ from exam dumps →
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.