PCDE Practice Question: Deploy scalable and highly available databases in Google Cloud
You are designing disaster recovery for a globally distributed application using Cloud Spanner with a multi-region configuration. The application requires an RPO of 0 and an RTO of less than 5 seconds in the event of a full region failure. Which Spanner configuration provides these guarantees?
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
✓
A multi-region Spanner instance with two read-write regions and one witness region.
A multi-region configuration with a leader region and at least two voting regions provides synchronous replication and automatic failover. Regional failover occurs within seconds, preserving zero data loss.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
A single-region Spanner instance with a read replica in another region.
Why it's wrong here
Read replicas are not synchronous and do not provide automatic failover.
- ✗
A multi-region Spanner instance with one read-write region and two read-only regions.
Why it's wrong here
Read-only regions do not vote in writes, so a single read-write region means a regional failure stops writes.
- ✗
A dual-region Spanner instance using default leader placement.
Why it's wrong here
Dual-region configurations (e.g., nam5) provide synchronous replication but may have higher write latency and still meet RTO requirements.
- ✓
A multi-region Spanner instance with two read-write regions and one witness region.
Why this is correct
Correct: a multi-region instance with at least two read-write regions can achieve synchronous replication and automatic failover within seconds.
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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.