Disaster Recovery practice questions

S3 lifecycle transition to Glacier Flexible Retrieval

Why wrong: Lifecycle transition changes storage class, not Region.

An EBS snapshot schedule

Why wrong: EBS snapshots do not apply to S3 objects.

A CloudFront distribution

Why wrong: CloudFront caches content but is not a durable DR copy.

Pilot light: keep only essential infrastructure in the secondary location and scale up the application during a failure.

Why wrong: Pilot light reduces cost by running only minimal components, but the application tier is not already running. That typically makes recovery slower than designs that keep a partial, production-like stack ready.

Active-active: run full production in both the primary and secondary locations at the same time.

Why wrong: Active-active generally requires running full production workloads in both locations continuously. That is usually more expensive than the scenario described.

Backup and restore only: rely on periodic backups and restore the application after a failure.

Why wrong: Backup and restore provides disaster recovery without keeping a ready environment. Recovery is typically significantly slower because you must provision/restore services and data after the incident.

Backup and restore only, with no continuously running infrastructure in the secondary Region.

Why wrong: Backups with no warm infrastructure typically lead to longer recovery times and may miss a 6-hour RTO target.

Pilot light, keeping only the minimum resources needed to bootstrap the environment.

Why wrong: Pilot light usually provides very limited capacity and may still take too long to become fully operational within 6 hours.

Multi-site active-active, serving production traffic from both Regions at all times.

Why wrong: Active-active involves running full production in both Regions, which is more operationally complex and costlier than required.

An EBS snapshot schedule

Why wrong: EBS snapshots do not apply to S3 objects.

S3 lifecycle transition to Glacier Flexible Retrieval

Why wrong: Lifecycle transition changes storage class, not Region.

A CloudFront distribution

Why wrong: CloudFront caches content but is not a durable DR copy.

S3 lifecycle transition to Glacier Flexible Retrieval

Why wrong: Lifecycle transition changes storage class, not Region.

An EBS snapshot schedule

Why wrong: EBS snapshots do not apply to S3 objects.

A CloudFront distribution

Why wrong: CloudFront caches content but is not a durable DR copy.

Enable S3 lifecycle policies to automatically move objects to Glacier after 30 days only.

Why wrong: Lifecycle transitions help with cost and retention, but they do not protect against overwrites or provide cross-Region copies.

Disable all versioning and rely on AWS Backup to restore objects from a scheduled backup window.

Why wrong: Relying on backups may introduce recovery delays and does not give immediate protection from overwrites as versioning does.

Enable S3 Block Public Access and SSE-S3 encryption, without using versioning or replication.

Why wrong: Block Public Access and encryption improve security, but they do not address resilience to overwrites or Region-level failures.

Backup and restore only, because the existing daily backups are already in another Region.

Why wrong: Backup and restore typically takes too long to rebuild the environment and recover data for a 45-minute RTO, especially when application tiers and databases both need to be restored and validated.

Pilot light, because the recovery Region only needs minimal resources and can be scaled after a disaster.

Why wrong: Pilot light keeps only core components running in the recovery Region. That is cheaper, but it usually requires too much time to scale and activate the full stack to meet a 45-minute RTO.

Active-active, because it minimizes RTO by keeping both Regions fully live all the time.

Why wrong: Active-active provides the fastest recovery, but it is typically the most expensive option because both Regions must be fully provisioned and operating all the time. That conflicts with the stated budget constraint.

Move all objects to S3 Glacier Instant Retrieval and apply a lifecycle policy to keep only the latest object copy.

Why wrong: Glacier storage tiers do not prevent deletion of the latest version, and keeping only the latest copy fails the recovery requirement.

Use S3 server-side encryption with KMS keys and rely on access logs to manually recover the deleted objects.

Why wrong: Encryption protects confidentiality but does not retain deleted data, and access logs do not reconstruct object contents.

Enable S3 bucket policies that deny DeleteObject, but do not enable versioning or replication.

Why wrong: A deny policy can reduce future mistakes, but it does not provide recovery for the already-deleted objects or disaster resilience.

An EBS snapshot schedule

Why wrong: EBS snapshots do not apply to S3 objects.

S3 lifecycle transition to Glacier Flexible Retrieval

Why wrong: Lifecycle transition changes storage class, not Region.

A CloudFront distribution

Why wrong: CloudFront caches content but is not a durable DR copy.

A single-AZ Aurora cluster

Why wrong: Single-AZ design does not provide cross-Region DR.

Manual snapshots copied monthly

Why wrong: Monthly snapshots create high RPO and slow recovery.

An ElastiCache Redis replica

Why wrong: ElastiCache is not an Aurora database DR mechanism.

A single-AZ Aurora cluster

Why wrong: Single-AZ design does not provide cross-Region DR.

An ElastiCache Redis replica

Why wrong: ElastiCache is not an Aurora database DR mechanism.

Manual snapshots copied monthly

Why wrong: Monthly snapshots create high RPO and slow recovery.

An EBS snapshot schedule

Why wrong: EBS snapshots do not apply to S3 objects.

S3 lifecycle transition to Glacier Flexible Retrieval

Why wrong: Lifecycle transition changes storage class, not Region.

A CloudFront distribution

Why wrong: CloudFront caches content but is not a durable DR copy.

An EBS snapshot schedule

Why wrong: EBS snapshots do not apply to S3 objects.

S3 lifecycle transition to Glacier Flexible Retrieval

Why wrong: Lifecycle transition changes storage class, not Region.

A CloudFront distribution

Why wrong: CloudFront caches content but is not a durable DR copy.

Wait for AWS to automatically fail over the read replica to become the new primary

Why wrong: RDS cross-region read replicas do not automatically failover. Manual promotion is required. Only Multi-AZ provides automatic same-region failover.

Restore the primary database from the most recent automated snapshot in us-west-2

Why wrong: The read replica is more current than a daily snapshot and is faster to promote. Snapshot restoration is the last resort when no replica exists.

Create a new RDS instance in us-west-2 and manually restore data from application logs

Why wrong: Manually restoring data from application logs is not a valid DR procedure. Use the read replica which already contains synchronized production data.

S3 lifecycle transition to Glacier Flexible Retrieval

Why wrong: Lifecycle transition changes storage class, not Region.

An EBS snapshot schedule

Why wrong: EBS snapshots do not apply to S3 objects.

A CloudFront distribution

Why wrong: CloudFront caches content but is not a durable DR copy.

Enable S3 lifecycle policies to automatically move objects to Glacier after 30 days only.

Why wrong: Lifecycle transitions help with cost and retention, but they do not protect against overwrites or provide cross-Region copies.

Disable all versioning and rely on AWS Backup to restore objects from a scheduled backup window.

Why wrong: Relying on backups may introduce recovery delays and does not give immediate protection from overwrites as versioning does.

Enable S3 Block Public Access and SSE-S3 encryption, without using versioning or replication.

Why wrong: Block Public Access and encryption improve security, but they do not address resilience to overwrites or Region-level failures.

A single-AZ Aurora cluster

Why wrong: Single-AZ design does not provide cross-Region DR.

An ElastiCache Redis replica

Why wrong: ElastiCache is not an Aurora database DR mechanism.

Manual snapshots copied monthly

Why wrong: Monthly snapshots create high RPO and slow recovery.

Move all objects to S3 Glacier Instant Retrieval and apply a lifecycle policy to keep only the latest object copy.

Why wrong: Glacier storage tiers do not prevent deletion of the latest version, and keeping only the latest copy fails the recovery requirement.

Use S3 server-side encryption with KMS keys and rely on access logs to manually recover the deleted objects.

Why wrong: Encryption protects confidentiality but does not retain deleted data, and access logs do not reconstruct object contents.

Enable S3 bucket policies that deny DeleteObject, but do not enable versioning or replication.

Why wrong: A deny policy can reduce future mistakes, but it does not provide recovery for the already-deleted objects or disaster resilience.

Enable EBS multi-attach to spread the workload across AZs and replicate snapshots automatically between Regions.

Why wrong: Multi-attach increases concurrent access within certain designs but does not replicate data between Regions.

Use RDS read replicas in another Region and keep the analytics dataset in an RDS instance only.

Why wrong: RDS replicas address database workloads, not EBS volume snapshots for existing EC2-backed storage.

Rely on instance store for durability and copy only AMIs across Regions.

Why wrong: Instance store is not reliable durable storage, and copying AMIs alone does not capture EBS volume data.