Disaster recovery strategies in GCP - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding RTO and RPO in Disaster Recovery

Which statement correctly describes the difference between Recovery Time Objective (RTO) and Recovery Point Objective (RPO) in disaster recovery?

A RTO is the maximum acceptable time to restore services after a disaster; RPO is the maximum acceptable data loss measured in time.

B RTO is the maximum data loss allowed; RPO is the time it takes to restore services after a disaster.

C RTO and RPO both measure the time to restore services but in different units.

D RTO measures data loss in bytes; RPO measures downtime in hours.

💡 Hint

Think about what each objective aims to limit: downtime or data loss.

RTO defines how quickly you want to recover your system after a failure. RPO defines how much data loss is acceptable, measured by time since last backup.

❓ Architecture

intermediate

Choosing a Disaster Recovery Architecture in GCP

You want to design a disaster recovery solution for a critical application on Google Cloud Platform. The application requires minimal downtime and data loss. Which architecture best fits this need?

A Backup and restore: Periodic backups stored in Cloud Storage, restore when needed.

B Pilot light: Minimal critical components running in a secondary region, scaled up on disaster.

C Warm standby: A scaled-down version of the full environment running in a secondary region, ready to scale up.

D Cold standby: No resources running in the secondary region until disaster occurs.

💡 Hint

Consider which option balances readiness and cost for minimal downtime.

Warm standby keeps a scaled-down environment running, allowing quick scaling and minimal downtime, suitable for critical apps.

❓ Configuration

advanced

Configuring Cross-Region Replication for Cloud Storage

Which configuration snippet correctly enables cross-region replication for a Google Cloud Storage bucket named 'source-bucket' to replicate objects to 'destination-bucket' in another region?

GCP

gsutil versioning set on gs://source-bucket

# Replication configuration below

A gsutil bucket replication set --source=source-bucket --destination=destination-bucket --location=us-east1

B gsutil replication create gs://source-bucket gs://destination-bucket

C gsutil replication create --source=source-bucket --destination=destination-bucket --location=us-central1

D gsutil replication set --source=source-bucket --destination=destination-bucket --location=us-east1

💡 Hint

Check the correct gsutil command syntax for bucket replication creation.

The correct command is 'gsutil replication create gs://source-bucket gs://destination-bucket'.

❓ security

advanced

Securing Disaster Recovery Access in GCP

To ensure secure access to disaster recovery resources in a secondary region, which IAM policy practice is best?

A Grant all users the Editor role on the recovery project for quick access.

B Disable IAM policies on the recovery project to prevent accidental lockout.

C Assign Owner role to all team members on the recovery project to avoid delays.

D Use least privilege principle by granting only necessary roles to specific users or groups.

💡 Hint

Think about minimizing risk while allowing access.

Granting only necessary permissions to specific users follows best security practices and reduces risk.

❓ service_behavior

expert

Behavior of Multi-Region Failover with Cloud SQL

In a Cloud SQL instance configured with high availability across multiple regions, what happens automatically when the primary region becomes unavailable?

A Cloud SQL automatically fails over to the standby instance in the secondary region with minimal downtime.

B Cloud SQL requires manual intervention to switch to the standby instance in the secondary region.

C Cloud SQL stops serving traffic until the primary region is restored.

D Cloud SQL creates a new instance in a different region and migrates data automatically.

💡 Hint

Consider how managed services handle failover for high availability.

Cloud SQL automatically fails over to the standby instance in the secondary region with minimal downtime.

Practice

1. What is the main goal of a disaster recovery strategy in cloud infrastructure?

easy

A. To improve user interface design

B. To keep services running during unexpected problems

C. To increase the speed of data processing

D. To reduce the cost of cloud services

Solution

1. Step 1: Understand disaster recovery purpose

   Disaster recovery aims to keep systems available and data safe during failures or disasters.

2. Step 2: Identify the main goal

   The main goal is to maintain service uptime and data integrity despite problems.

3. Final Answer:

   To keep services running during unexpected problems -> Option B

4. Quick Check:

   Disaster recovery = keep services safe [OK]

Hint: Disaster recovery means service stays up during trouble [OK]

Common Mistakes:

• Confusing disaster recovery with cost saving
• Thinking it improves speed or UI
• Ignoring service availability

2. Which GCP service is commonly used to store backups for disaster recovery?

easy

A. Cloud Pub/Sub

B. Google Compute Engine

C. Google Kubernetes Engine

D. Google Cloud Storage

Solution

1. Step 1: Identify backup storage service

   Backups need durable, scalable storage. Google Cloud Storage is designed for this.

2. Step 2: Exclude compute and messaging services

   Compute Engine and Kubernetes Engine run workloads, Pub/Sub handles messaging, not backups.

3. Final Answer:

   Google Cloud Storage -> Option D

4. Quick Check:

   Backup storage = Cloud Storage [OK]

Hint: Backups go to Cloud Storage, not compute or messaging [OK]

Common Mistakes:

• Choosing compute services for backup storage
• Confusing messaging service with storage
• Not knowing Cloud Storage purpose

3. Consider this GCP setup code snippet for disaster recovery:

resource "google_compute_instance" "primary" {
  name         = "primary-instance"
  zone         = "us-central1-a"
  machine_type = "e2-medium"
  boot_disk {
    initialize_params {
      image = "debian-cloud/debian-11"
    }
  }
}

resource "google_compute_instance" "backup" {
  name         = "backup-instance"
  zone         = "us-central1-b"
  machine_type = "e2-medium"
  boot_disk {
    initialize_params {
      image = "debian-cloud/debian-11"
    }
  }
}

What is the main benefit of this configuration for disaster recovery?

medium

A. It creates two instances in different zones to improve availability

B. It reduces the cost by using smaller machines

C. It backs up data automatically to Cloud Storage

D. It enables faster network speed between instances

Solution

1. Step 1: Analyze instance zones

   The two instances are in different zones (us-central1-a and us-central1-b), which protects against zone failure.

2. Step 2: Identify disaster recovery benefit

   Having instances in separate zones improves availability and fault tolerance during disasters.

3. Final Answer:

   It creates two instances in different zones to improve availability -> Option A

4. Quick Check:

   Multi-zone instances = better availability [OK]

Hint: Different zones mean better uptime during failures [OK]

Common Mistakes:

• Assuming cost reduction is main goal
• Thinking data backup happens automatically
• Confusing network speed with disaster recovery

4. You have a disaster recovery plan that uses snapshots for backups. After a disaster, the recovery fails because snapshots are missing. What is the most likely error?

medium

A. Snapshots were stored in the same zone as the primary data

B. Snapshots were not scheduled regularly

C. Snapshots were encrypted with the wrong key

D. Snapshots were created from the wrong disk

Solution

1. Step 1: Understand snapshot storage risk

   If snapshots are stored only in the same zone, a zone failure can destroy both primary data and backups.

2. Step 2: Identify cause of missing snapshots

   Storing snapshots in the same zone risks losing them during a disaster affecting that zone.

3. Final Answer:

   Snapshots were stored in the same zone as the primary data -> Option A

4. Quick Check:

   Backups must be in different zones [OK]

Hint: Backups in same zone vanish with disaster [OK]

Common Mistakes:

• Ignoring backup location importance
• Assuming encryption or disk choice caused failure
• Not scheduling snapshots regularly

5. You want to design a disaster recovery plan for a critical GCP application that must recover within minutes after a regional outage. Which combination of strategies is best?

hard

A. Use multi-zone deployment with weekly snapshots and manual recovery

B. Use single-zone deployment with daily manual backups to Cloud Storage

C. Use multi-region deployment with automated failover and continuous data replication

D. Use single-region deployment with monthly backups and no failover

Solution

1. Step 1: Identify recovery time objective (RTO)

   Recovery within minutes requires fast failover and minimal data loss.

2. Step 2: Evaluate strategies for fast recovery

   Multi-region deployment with automated failover and continuous replication ensures quick switch and up-to-date data.

3. Step 3: Compare with other options

   Single-zone or single-region with manual backups are slower and risk data loss; weekly or monthly backups are too infrequent.

4. Final Answer:

   Use multi-region deployment with automated failover and continuous data replication -> Option C

5. Quick Check:

   Fast recovery needs multi-region + automation [OK]

Hint: Fast recovery needs multi-region and automation [OK]

Common Mistakes:

• Choosing single-zone or single-region for critical apps
• Relying on manual backups for quick recovery
• Ignoring continuous data replication