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PCDE Cloud Spanner regional instance Practice Question
A company is designing a disaster recovery strategy for their Cloud Spanner database. They need an RPO of less than 30 seconds and an RTO of less than 1 minute. Which two configurations would meet these requirements? (Choose TWO)
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
✓
Multi-region configuration with read-write replicas (e.g., nam3)
The correct answers are B and D. A multi-region configuration with read-write replicas (e.g., nam3) provides automatic failover across regions with an RPO of approximately 15 seconds and an RTO of less than 1 minute, meeting the requirements for region-level failures. A regional instance in Cloud Spanner provides synchronous replication within the region, achieving an RPO of zero and an RTO of seconds, which meets the requirements for zone-level failures within a region. Option A (cross-region backup and restore) typically has an RPO of hours and RTO of hours, so it does not meet the strict RPO/RTO. Option C (point-in-time recovery) provides RPO of seconds to minutes but depends on backups and may not achieve RTO <1 minute for restore operations. Option E (multi-region with read-only replicas) does not support automatic failover because read-only replicas cannot become the new leader, so failover is not automatic and RTO would be longer.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Cross-region backup and restore
Why it's wrong here
Backup restore has RPO measured in hours and RTO in hours, not meeting the requirements.
- ✓
Multi-region configuration with read-write replicas (e.g., nam3)
Why this is correct
A multi-region configuration with read-write replicas provides automatic failover with RPO ~15s and RTO < 1min.
- ✗
Point-in-time recovery (PITR)
Why it's wrong here
PITR is for recovering to a specific point in time, not for automatic failover.
- ✓
Regional instance
Why this is correct
A regional instance provides RPO=0 and automatic failover within the region (RTO seconds), meeting RPO<30s and RTO<1min.
- ✗
Multi-region configuration with read-only replicas
Why it's wrong here
Read-only replicas do not provide automatic failover; they are for reads only.
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Variation 1. An organization needs to design a disaster recovery plan for Cloud SQL for PostgreSQL with an RPO of 10 seconds and an RTO of 5 minutes. Which TWO solutions meet these requirements? (Choose 2)
medium- ✓ A.Cloud SQL cross-region read replica with manual promotion.
- B.Export the database to Cloud Storage and import in another region.
- ✓ C.Cloud SQL HA with automatic failover to standby in the same region.
- D.Cloud SQL point-in-time recovery from backups.
- E.Use Cloud SQL automated backups with cross-region copy.
Why A: Cloud SQL HA provides near-zero RPO and RTO under 60 seconds within the same region. Cross-region read replicas can achieve RPO of seconds if replication lag is low, and manual promotion takes minutes.
Variation 2. A Cloud SQL for PostgreSQL instance needs to achieve a recovery point objective (RPO) of less than 1 minute and a recovery time objective (RTO) of less than 2 minutes in the event of a zone failure. Which disaster recovery strategy should be used?
easy- A.Perform regular backups to Cloud Storage and restore in a different zone.
- B.Enable cross-region replication using a read replica.
- C.Enable point-in-time recovery (PITR) with transaction log backups.
- ✓ D.Configure Cloud SQL HA (high availability) with a standby in a different zone.
Why D: Cloud SQL HA configuration provides automatic failover to a standby in a different zone within the same region, with RPO near zero and RTO typically under 60 seconds. Cross-region read replicas have RPO equal to replication lag (could be minutes) and RTO of minutes due to manual promotion. Cross-region backup restore has RPO equal to backup age (hours) and RTO of hours. Point-in-time recovery (PITR) is for within-region data recovery, not zone failure failover.
Variation 3. 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?
hard- A.A single-region Spanner instance with a read replica in another region.
- B.A multi-region Spanner instance with one read-write region and two read-only regions.
- C.A dual-region Spanner instance using default leader placement.
- ✓ D.A multi-region Spanner instance with two read-write regions and one witness region.
Why D: 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.
Variation 4. An application running on Compute Engine needs a relational database with high availability across zones within a single region. The application requires an RTO of less than 30 seconds and RPO of zero. Which database solution meets these requirements?
easy- ✓ A.AlloyDB
- B.Cloud Bigtable with replication
- C.Cloud SQL for MySQL with HA configuration
- D.Cloud Spanner multi-region
Why A: AlloyDB provides automatic failover with RTO of less than 30 seconds and near-zero data loss (RPO ~0). It replicates data synchronously within a primary and read pool across zones in the same region. Cloud SQL HA has RTO <60 seconds, which does not meet the <30 second requirement. Spanner multi-region is overkill and has higher cost. Bigtable does not support SQL and has eventual consistency.
Variation 5. A company needs to ensure that their Cloud SQL for PostgreSQL instance can recover from a zonal failure within 60 seconds with minimal data loss. Which feature should they enable?
easy- A.Automated backups with PITR
- B.Cross-region read replica
- C.Enable deletion protection
- ✓ D.High availability (HA) configuration
Why D: Cloud SQL HA configuration automatically fails over to a standby instance in a different zone within the same region. This failover is automatic and typically completes in under 60 seconds, with near-zero data loss (synchronous replication). Cross-region replicas are manual and have longer RTO. Backups are not suitable for quick recovery.
Variation 6. A company uses Cloud Spanner with a single-region configuration in us-central1. They need to improve disaster recovery to meet an RPO of zero and an RTO of less than 5 seconds across regions. Which three actions should they take? (Choose three.)
hard- A.Add a cross-region read replica to the existing single-region instance
- ✓ B.Use backup/restore to migrate data from the single-region instance to the new multi-region instance
- C.Enable point-in-time recovery (PITR) with 7-day retention
- ✓ D.Update application connection strings to point to the multi-region instance
- ✓ E.Create a new multi-region Spanner instance with a two-region configuration (e.g., nam6)
Why B: To achieve RPO=0 and RTO<5s across regions, you need a multi-region Spanner configuration with synchronous replication. You cannot achieve cross-region RPO=0 with a single-region instance. Therefore, you must migrate to a multi-region configuration. The steps include: 1) Create a new multi-region instance (e.g., nam6) with the desired config, 2) Migrate data from the single-region instance to the multi-region instance (e.g., using backup/restore or Dataflow), 3) Update application connection strings to point to the new instance. Optionally, you can perform a rolling migration to minimize downtime. Using cross-region read replicas is not possible for Spanner (Spanner does not have read replicas in the same sense; it uses replica types within an instance).
Variation 7. A global financial services company requires a multi-region Spanner instance with an RPO of zero and an RTO of less than 5 seconds for a critical transactional workload. The application writes to a single region and reads from multiple regions. Which Spanner configuration should they choose?
hard- A.A single-region configuration with read replicas in multiple zones
- ✓ B.A two-region multi-region configuration (e.g., nam6)
- C.A dual-region configuration with two read-write regions and one read-only region
- D.A three-region multi-region configuration (e.g., nam-eur-asia1)
Why B: For zero RPO and sub-5-second RTO, a multi-region configuration with synchronous replication is needed. Spanner multi-region configurations like nam6 use synchronous replication across a primary and secondary region (with both read-write replicas). The leader region handles writes, and read-only replicas are for reads. A two-region multi-region config (e.g., nam6) provides synchronous replication (RPO=0) and automatic failover in <5 seconds. Three-region configs (nam-eur-asia1) have higher write latency due to longer distances.
Variation 8. A team is designing a disaster recovery plan for a Cloud Spanner instance. They want an RPO of 10 minutes and RTO of 5 minutes. Which two features should they use?
easy- ✓ A.Enable point-in-time recovery (PITR) with a 10-minute recovery period
- B.Deploy a cross-region read replica
- C.Configure automated backups
- D.Use database versioning to failover
- ✓ E.Set up a multi-region configuration
Why A: Point-in-time recovery (PITR) with a 10-minute recovery period is correct because it allows restoring Cloud Spanner data to any point within the last 10 minutes, meeting the RPO of 10 minutes. PITR provides versioned data retention without requiring manual backups, enabling recovery within seconds to minutes, which satisfies the RTO of 5 minutes when combined with a multi-region configuration.
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.