RDS Multi AZ practice questions

Refactor the Node.js frontend to run on AWS Lambda with Amazon API Gateway

Why wrong: Lambda is suitable for Node.js, but the question asks for TWO strategies; the Java backend and database are better candidates for modernization.

Migrate the database to Amazon DynamoDB

Why wrong: DynamoDB is NoSQL and would require application changes.

Deploy the Java backend on Amazon EC2 with Auto Scaling

Why wrong: EC2 requires managing servers; not as modernized as Fargate.

Use automated backups with 5-minute retention.

Why wrong: Automated backups are not for failover.

Take manual snapshots every 5 minutes and copy to another region.

Why wrong: Snapshot restore takes longer than 15 minutes.

Create a cross-region read replica in us-west-2.

Why wrong: Asynchronous replication may exceed RPO.

Configure an in-memory cache like Amazon ElastiCache to cache frequent queries.

Why wrong: Caching reduces read load but not writes; still CPU contention may remain.

Increase the instance size of the RDS DB instance to a larger instance type.

Why wrong: Vertical scaling may help temporarily but is not as efficient as offloading reads.

Enable Multi-AZ for the RDS instance to distribute the load across two instances.

Why wrong: Multi-AZ is for high availability, not read scaling.

Amazon DynamoDB with DAX

Why wrong: DynamoDB is NoSQL, not relational.

Amazon RDS with Multi-AZ deployment

Why wrong: Multi-AZ is for high availability, not read scaling.

Amazon ElastiCache for Redis

Why wrong: ElastiCache is a cache, not a relational database.

Use AWS Global Accelerator to reduce data transfer costs

Why wrong: Global Accelerator improves performance but does not reduce internal cross-AZ costs.

Place all web tier instances in one AZ and all application tier instances in another AZ

Why wrong: This increases cross-AZ traffic and costs.

Use a single AZ for all tiers to avoid cross-AZ traffic

Why wrong: Single AZ reduces high availability.

Create a Route 53 Resolver rule in the central account to forward queries to the private hosted zone.

Why wrong: Resolver rules are for outbound queries, not for authorization.

Create a VPC peering connection between the central account and each VPC.

Why wrong: VPC peering is not needed for Route 53 private hosted zones.

Use AWS Config aggregator to view resources.

Why wrong: Config aggregator is for resource configuration, not metrics.

Use Amazon QuickSight with data sources from each account.

Why wrong: Not designed for CloudWatch dashboards.

Use AWS CloudFormation StackSets to deploy dashboards in each account.

Why wrong: Does not aggregate.

Use Amazon SQS to buffer write requests to the database.

Why wrong: SQS does not address connection pooling; it would add latency.

Use DynamoDB Accelerator (DAX) as a caching layer.

Why wrong: DAX caches DynamoDB, not RDS.

Increase the max_connections parameter in the RDS parameter group.

Why wrong: Increasing max_connections may hit instance limits and is not a scalable solution.

Increase the data retention period to 365 days.

Why wrong: Longer retention allows reprocessing but does not give independent throughput.

Use resharding to increase the number of shards.

Why wrong: Resharding changes shard count but does not provide independent processing or time-based reprocessing.

Use the Kinesis Client Library (KCL) with checkpointing.

Why wrong: KCL manages checkpoints but does not provide dedicated throughput per consumer or easy time-based reprocessing.

RDS Multi-AZ in the same region

Why wrong: Multi-AZ only protects within a region, not cross-region.

Amazon S3

Why wrong: S3 is not a database DR solution.

AWS Database Migration Service

Why wrong: DMS is for migration, not continuous DR.

Use Amazon Aurora Global Database.

Why wrong: Aurora Global Database is for Aurora, not RDS MySQL.

Use Amazon RDS with automated backups and restore in another Region.

Why wrong: Restoring from backup would take longer than 1 minute, not meeting the RTO.

Use Amazon RDS Multi-AZ with a standby in a different AWS Region.

Why wrong: RDS Multi-AZ only supports standby in the same region, not cross-region.

Amazon EBS volumes

Why wrong: EBS volumes are tied to a single AZ and are not highly available across AZs.

Amazon EC2 instances

Why wrong: EC2 instances are not inherently highly available; they require an Auto Scaling group and load balancer.

Amazon S3

Why wrong: S3 is highly available across multiple AZs, but the question likely expects ELB and RDS Multi-AZ as the typical correct answers.

Launch the database instance in a public subnet.

Why wrong: Public subnets are internet-facing; database should be in private subnet.

Store database credentials in AWS Systems Manager Parameter Store.

Why wrong: This is a best practice but does not address network security.

Use AWS Database Migration Service (DMS) for continuous replication to us-west-2

Why wrong: DMS is for migration, not DR, and adds cost.

Use automated backups and restore to us-west-2 when needed

Why wrong: Restore from backup takes longer than 15 minutes.

Use a Multi-AZ deployment in us-east-1 and failover to a standby instance

Why wrong: Multi-AZ is within region, not cross-region DR.

Use Amazon ElastiCache for Memcached as the primary database.

Why wrong: Memcached is a cache, not a relational database.

Deploy Amazon RDS in a Multi-AZ configuration without read replicas.

Why wrong: Multi-AZ alone does not address read spikes.

Deploy Amazon RDS in a single Availability Zone with a large instance size.

Why wrong: Single-AZ is not highly available.

AWS Global Accelerator with the ALB as the endpoint

Why wrong: Global Accelerator improves latency by routing traffic to the nearest healthy endpoint, but it does not cache content. Static content would still be served from the ALB.

Amazon CloudFront with the ALB as the origin

Why wrong: This configuration would send all traffic to the ALB, not caching static content separately. CloudFront would cache responses from the ALB, but the ALB would still handle all requests.

Amazon S3 Transfer Acceleration for static content

Why wrong: S3 Transfer Acceleration is for uploading to S3, not for serving content to users. It does not cache or accelerate delivery.

Use EC2 AMI copy to another region and launch instances from the AMI.

Why wrong: AMI copy and instance launch can exceed 15 minutes.

Use RDS cross-region snapshots and restore in the DR region.

Why wrong: Snapshot restore takes longer than 15 minutes.

Configure RDS Multi-AZ in the primary region.

Why wrong: Multi-AZ is for HA within a region, not DR.

Amazon RDS Multi-AZ

Why wrong: RDS Multi-AZ is within a single region and does not provide cross-region read replicas.

Amazon ElastiCache for Redis global datastore

Why wrong: ElastiCache is a cache, not a durable database for primary data.

Amazon DynamoDB global tables

Why wrong: DynamoDB global tables are eventually consistent and do not support active-active writes for low-latency writes.

Amazon S3

Why wrong: Amazon S3 has higher latency and is not designed for sub-millisecond access patterns. It is better suited for object storage, not stateful data requiring low-latency reads/writes.

Amazon RDS with Multi-AZ

Why wrong: Amazon RDS provides relational databases with Multi-AZ for high availability, but it has higher latency than DynamoDB for simple key-value operations and is not as scalable.

Amazon ElastiCache for Redis

Why wrong: Amazon ElastiCache is an in-memory cache, not a durable data store by default. While it can be made durable with persistence, it is typically used for caching, not as the primary data store.