Design innovative, scalable, and highly available cloud database solutions →hardMultiple ChoiceObjective-mapped
PCDE Practice Question: Design innovative, scalable, and highly available cloud database solutions
You are planning a Cloud Bigtable cluster for a workload requiring 100,000 reads per second and 50,000 writes per second. The data will be stored on HDD. How many nodes are needed for the projected throughput? (Assume each node provides 10,000 QPS for reads or writes.)
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
✓
10 nodes
Each Bigtable node can handle 10,000 QPS for reads or writes. For 100,000 reads/s, need 10 nodes. For 50,000 writes/s, need 5 nodes. The node count must satisfy both: max(10,5)=10 nodes. Also storage capacity may be a factor but the question focuses on throughput.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
20 nodes
Why it's wrong here
20 nodes are more than needed.
- ✗
5 nodes
Why it's wrong here
5 nodes provide 50,000 reads/s, insufficient for 100,000 reads.
- ✗
15 nodes
Why it's wrong here
15 nodes exceed requirements.
- ✓
10 nodes
Why this is correct
10 nodes provide 100,000 reads/s and 100,000 writes/s, covering both.
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Variation 1. You need to estimate the number of Bigtable nodes required for a workload of 50,000 reads per second (QPS) and 20,000 writes per second. Each node can handle 10,000 QPS for reads or writes. Storage is not a constraint. What is the minimum number of nodes required?
hard- A.2 nodes
- B.7 nodes
- ✓ C.5 nodes
- D.10 nodes
Why C: Reads require 50,000/10,000 = 5 nodes. Writes require 20,000/10,000 = 2 nodes. The higher value is the bottleneck, so 5 nodes are needed.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This PCDE practice question is part of Courseiva's free Google Cloud 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 PCDE exam.