AWS Certified Solutions Architect - Associate SAA-C03 Practice Test 52
Question 510
An application requires POSIX file locking and one shared media workspace mounted by EC2 instances across multiple Availability Zones. Teams want the shared storage to remain available when an instance is replaced. Which managed AWS file storage fits?
- Use Amazon EFS with appropriate mount targets and access controls across the required Availability Zones.
- Use S3 object PUT requests as a drop-in POSIX shared file system with standard lock semantics.
- Keep assets only in one EC2 instance-store directory and route all users to that instance forever.
- Use a separate ordinary EBS volume on each instance and assume all writes replicate instantly between volumes.
Explanation
Correct Answer
A:EFS provides managed network file-system semantics and can be accessed from multiple supported EC2 instances rather than binding data to one host's block device.
Incorrect Answers
B:Object storage has different consistency and filesystem semantics than a mounted NFS shared file service.
C:Instance-store data is ephemeral and not a resilient, multi-AZ shared filesystem.
D:Independent EBS volumes do not automatically synchronize a shared POSIX workspace or file locking.
Question 511
A transactional EC2 workload needs low-latency persistent block storage in one AZ and regular crash-recovery snapshots. A teammate proposes storing a mounted database write-ahead log as S3 object keys. Which storage layer is more appropriate?
- Use EC2 ephemeral instance store alone and assume it survives termination as a persistent protected volume.
- Mount an Amazon S3 bucket using Mountpoint for Amazon S3 and use that mount directly for crash-synchronous database write-ahead-log updates.
- Use an EBS block volume with suitable performance and snapshot protection for the instance's persistent local disk needs.
- Use Amazon S3 File Gateway as the exclusive local write-ahead-log volume and rely on its asynchronous object uploads for each committed transaction.
Explanation
Correct Answer
C:EBS presents a block device to EC2 and supports persistent data volumes with snapshot capabilities, unlike object-store API semantics.
Incorrect Answers
A:Instance-store lifecycle differs from persistent EBS and does not supply retained snapshot-backed block storage.
B:Mountpoint provides S3 object-backed file operations, not the full mutable POSIX/block-device behavior required for repeated WAL writes, append, and database crash-recovery sync semantics. An EBS volume suits the local block requirement.
D:S3 File Gateway buffers file writes locally and uploads objects asynchronously. That transfer model is not an equivalent replacement for a directly attached, persistent low-latency block device with the database’s required WAL durability semantics.
Question 512
A digital publisher serves immutable product thumbnails and PDFs to users worldwide. The content does not require file locking or shared POSIX mounts. Which architecture is simplest and scalable?
- Build a multi-AZ POSIX file share solely so browsers can mount an NFS volume across the public internet.
- Place every thumbnail on a separate instance-local EBS disk and force each user to connect to that one server.
- Send PDF bytes through SQS ReceiveMessage to each browser instead of exposing a content endpoint.
- Store the immutable objects in Amazon S3 and distribute them through CloudFront with appropriate caching.
Explanation
Correct Answer
D:S3 provides durable object storage, while CloudFront edge caching efficiently serves repeated global HTTP content without shared filesystem management.
Incorrect Answers
A:Browsers normally use HTTP content delivery; exposing file-share semantics adds unnecessary complexity and risk.
B:Per-host disks complicate replication and do not offer the simple global object-serving pattern requested.
C:Queue receive APIs are not a scalable public HTTP file distribution or CDN cache interface.
Question 513
A customer portal runs behind an ALB, but all six healthy EC2 targets are placed in one Availability Zone. The service must survive loss of that entire zone without manual restoration. What deployment changes are essential?
- Add a second ALB listener with another URL path but keep every target in the original AZ.
- Increase each instance's EBS disk size and assume the database, network and compute become multi-AZ.
- Increase the number of instances from six to twelve in the same original AZ only.
- Distribute healthy application targets across at least two AZs behind the load balancer and maintain adequate spare capacity.
Explanation
Correct Answer
D:Multiple targets in a single AZ share a zonal failure domain. Cross-AZ target placement lets the ALB continue serving from unaffected capacity.
Incorrect Answers
A:Listener count does not add independent compute failure domains or recover the lost zone.
B:Storage capacity changes cannot provide redundant application instances across a different AZ.
C:Additional same-zone servers still become unavailable together when their shared AZ fails.
Question 514
A two-AZ EC2 Auto Scaling group has an attached ALB target group with application health checks. A defective web instance still passes EC2 status checks but its ALB target reports Unhealthy. The ALB avoids directing normal traffic to it, yet the instance remains in the Auto Scaling group indefinitely because the group currently uses only EC2 health checks. How should the team enable automatic instance replacement?
- Turn on Elastic Load Balancing health checks for the Auto Scaling group, retaining a suitable instance health-check grace period.
- Keep only EC2 status checks and assume an ALB target status of Unhealthy automatically replaces instances in every Auto Scaling group.
- Add another ALB listener rule for the same target and assume listener matching terminates and replaces broken EC2 instances.
- Increase only the ALB idle timeout so the Auto Scaling group learns that the underlying application has failed.
Explanation
Correct Answer
A:When an attached load balancer reports a registered target unhealthy, an Auto Scaling group with ELB health checks enabled can mark and replace that EC2 instance. A realistic grace period avoids premature replacements during startup.
Incorrect Answers
B:EC2 status checks may continue to report the VM as healthy when its application is broken. Auto Scaling ignores load balancer target-health results until the optional ELB health checks are configured.
C:Listener routing chooses targets for requests but does not directly change Auto Scaling health-source configuration or replace an unhealthy EC2 instance.
D:An ALB idle timeout governs connection handling, not the Auto Scaling group’s choice of which health checks may trigger automatic instance replacement.
Question 515
A retail site has EC2 instances in two AZs behind an ALB. After an AZ outage, healthy targets in the remaining AZ serve traffic but capacity drops by half. How can the fleet replenish lost target instances automatically?
- Wait for staff to manually launch every replacement from an interactive SSH shell after customer complaints.
- Run an Auto Scaling group across supported AZs with health checks and sufficient desired/max capacity.
- Set S3 object replication to replicate the ALB target-group membership across AZs.
- Keep desired capacity fixed at zero so the ALB has fewer unhealthy targets to monitor.
Explanation
Correct Answer
B:An Auto Scaling group replaces unhealthy or lost instances and can launch in surviving eligible AZs within quotas and capacity constraints.
Incorrect Answers
A:Manual recovery extends the outage and does not provide automatic replenishment of web capacity.
C:Object replication does not create replacement EC2 targets or adjust Auto Scaling desired capacity.
D:Zero desired servers remove serving capacity and cannot restore the regional fleet.
Question 516
A redundant two-AZ API fleet is autoscaled and load balanced, but all order history is stored only on the first EC2 node's local disk. That node fails while the rest of the fleet stays up. Why is the architecture not resilient?
- Turn on ALB sticky sessions and assume the failed node's old disk becomes available on a surviving instance.
- Disable autoscaling to preserve the original node indefinitely regardless of failure conditions.
- Externalize irreplaceable application state to durable, appropriately redundant storage rather than one web host.
- Increase ALB target count while keeping all order data exclusively on the first node's ephemeral filesystem.
Explanation
Correct Answer
C:Redundant compute cannot reconstruct transaction data stored on a failed single instance. State needs an independent persistence and recovery design.
Incorrect Answers
A:Session affinity affects request routing, not replication or recovery of a failed server's local storage.
B:Preventing planned replacement cannot stop hardware or zone failure from destroying access to single-host state.
D:More stateless targets do not make a single stateful disk available after its host is lost.
Question 517
A traditional Amazon RDS Multi-AZ deployment has a standby instance in another AZ. A reporting team wants to direct heavy read-only analytics to that standby to reduce load on the primary. Which statement is correct?
- Connect reporting clients directly to the Multi-AZ standby endpoint because standby is always a separately queryable read replica.
- Increase RDS backup retention because backups are live read replicas that service SQL joins.
- A traditional Multi-AZ standby is not a general read target; add supported read replicas or choose a suitable alternative DB deployment for read scaling.
- Use Route 53 weighted DNS to send reads to the standby's internal address, bypassing RDS failover management.
Explanation
Correct Answer
C:The standby in the traditional Multi-AZ DB instance model provides HA failover, rather than serving ordinary application reads.
Incorrect Answers
A:Traditional Multi-AZ DB standby semantics do not expose it as an arbitrary application read target.
B:Recovery artifacts are not general-purpose online read replicas for continuous analytics queries.
D:Manually targeting a standby undermines managed HA and does not create supported application reader semantics.
Question 518
A customer database fails over from the primary AZ to its RDS Multi-AZ standby. The application uses a small fixed database connection pool and many TCP sessions close during the promotion. What should the client do?
- Implement connection retry/reconnect behavior with appropriate DNS and timeout handling around RDS failover.
- Disable connection error handling so callers do not accidentally detect the failover.
- Increase the web server's root EBS volume size, which keeps every RDS client TCP session alive during AZ loss.
- Assume existing TCP connections continue byte-for-byte without interruption whenever RDS promotes a standby.
Explanation
Correct Answer
A:Multi-AZ helps restore database service availability but cannot preserve every in-flight socket and transaction through a primary change.
Incorrect Answers
B:Ignoring disconnects causes visible application failures rather than enabling recovery after the endpoint moves.
C:Unrelated web storage capacity has no power to preserve sockets through a database failover.
D:Database endpoint recovery may break established connections and require retry of interrupted operations.
Question 519
A production RDS database uses Multi-AZ for automatic failover. A bad application migration deletes an important table, and the same logical change reaches the standby. Which recovery capability must complement high availability?
- Use an ALB HTTP health check against the database endpoint as the database table restoration procedure.
- Force failover to the Multi-AZ standby because it always holds the table exactly as it existed before any logical deletion.
- Increase instance allocated IOPS because faster EBS storage automatically undeletes committed SQL tables.
- Use automated backups and point-in-time recovery or suitable independent backups to restore data before the destructive change.
Explanation
Correct Answer
D:HA protects service continuity against infrastructure failures; it does not rewind a successfully committed but incorrect SQL change.
Incorrect Answers
A:Health checks report reachability; they do not restore relational objects from historical backups.
B:Managed standby replication propagates committed changes and is not a point-in-time logical undo mechanism.
C:Storage performance does not reconstruct a prior database state after a valid destructive transaction.
Question 520
A SaaS relational database primary spends 85% CPU on SELECT reports while online orders need predictable write latency. The team can accept slightly stale reporting data. What database topology improves read capacity?
- Add another Multi-AZ standby to the traditional instance and query that standby for reports directly.
- Add appropriate RDS read replicas and direct eligible read-only reporting workloads to reader endpoints.
- Increase S3 object replication speed without changing relational database connections or read capacity.
- Disable every database index to make read queries cheaper when the primary is saturated.
Explanation
Correct Answer
B:Read replicas offload supported query workloads from the writer while preserving the primary for transaction updates; lag tolerance must match the business.
Incorrect Answers
A:A traditional standby exists for failover and is not a general independent SQL report reader.
C:Object replication is unrelated to the CPU consumed by the relational database's SELECT workload.
D:Unindexed queries can increase scans and CPU rather than creating additional query-serving capacity.