Running and coordinating multiple active environments increases infrastructure cost and operational complexity.
Incorrect! Try again.
21A company stores critical objects in an Amazon S3 bucket in one AWS Region. It requires copies to be created automatically in a second Region so that data remains available after a regional disruption. Which solution best meets this requirement?
AWS-native disaster recovery mechanisms and service orchestration for data durability and operational resilience
Medium
S3 Cross-Region Replication asynchronously copies eligible objects to a bucket in another Region, improving regional data durability.
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22An operations team must coordinate a disaster recovery workflow that restores a database, starts application instances, validates health, and updates DNS. The workflow must track each stage and retry failed tasks. Which AWS service is most suitable for the orchestration?
AWS-native disaster recovery mechanisms and service orchestration for data durability and operational resilience
Medium
A.AWS Step Functions
B.AWS Config
C.Amazon Inspector
D.Amazon CloudWatch Logs
Correct Answer: AWS Step Functions
Explanation:
AWS Step Functions coordinates multi-stage workflows, preserves execution state, and supports retries, error handling, and service integrations.
Incorrect! Try again.
23A company wants Route 53 to direct users to a disaster recovery endpoint only when the primary endpoint becomes unhealthy. Which routing policy should it configure?
AWS-native disaster recovery mechanisms and service orchestration for data durability and operational resilience
Medium
A.Geolocation routing
B.Weighted routing
C.Multivalue answer routing
D.Failover routing
Correct Answer: Failover routing
Explanation:
Route 53 failover routing uses health checks to return the secondary endpoint when the designated primary endpoint is unhealthy.
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24A company needs centrally managed, policy-based backups of Amazon EBS volumes, Amazon RDS databases, and Amazon EFS file systems. It also needs cross-Region backup copies. Which service should it use?
AWS-native disaster recovery mechanisms and service orchestration for data durability and operational resilience
Medium
A.AWS Application Migration Service
B.AWS Backup
C.AWS DataSync
D.Amazon S3 Glacier
Correct Answer: AWS Backup
Explanation:
AWS Backup centrally manages backup schedules, retention policies, and cross-Region copies for supported AWS resources.
Incorrect! Try again.
25A small internal application can tolerate an RTO of 12 hours and an RPO of 24 hours. The company wants the lowest ongoing disaster recovery cost. Which recovery pattern is the best fit?
Recovery architecture pattern: Backup and Restore
Medium
A.Backup and Restore
B.Warm Standby
C.Pilot Light
D.Multi-Site Active-Active
Correct Answer: Backup and Restore
Explanation:
Backup and Restore minimizes steady-state cost and is appropriate when the business can tolerate relatively long recovery and data-loss windows.
Incorrect! Try again.
26A database is backed up every 6 hours with no transaction-log replication between backups. If the primary Region fails just before the next backup, what is the approximate worst-case RPO?
Recovery architecture pattern: Backup and Restore
Medium
A.6 hours
B.24 hours
C.3 hours
D.12 hours
Correct Answer: 6 hours
Explanation:
With backups every 6 hours and no additional replication, nearly 6 hours of changes could be lost in the worst case.
Incorrect! Try again.
27A team can restore its database quickly, but recreating VPCs, load balancers, and application servers manually causes recovery delays and configuration errors. Which improvement most directly reduces this problem?
Recovery architecture pattern: Backup and Restore
Medium
A.Extend the backup retention period
B.Enable detailed billing reports
C.Increase the database backup frequency
D.Define the environment with infrastructure as code
Correct Answer: Define the environment with infrastructure as code
Explanation:
Infrastructure as code enables consistent, repeatable provisioning of the recovery environment and reduces manual configuration time.
Incorrect! Try again.
28A company copies database backups to a second Region but has never attempted a restore there. Which action provides the strongest evidence that its recovery objective is achievable?
Recovery architecture pattern: Backup and Restore
Medium
A.Run scheduled restore tests in the recovery Region
B.Review backup completion notifications each month
C.Increase backup retention from 30 to 60 days
D.Encrypt each backup with an AWS KMS key
Correct Answer: Run scheduled restore tests in the recovery Region
Explanation:
A successful backup does not prove recoverability. Scheduled restore tests validate backup integrity, permissions, dependencies, and recovery timing.
Incorrect! Try again.
29A company keeps a continuously replicated database and essential identity services running in its recovery Region. Application servers are created only after a disaster is declared. Which recovery pattern does this describe?
Recovery architecture pattern: Pilot Light
Medium
A.Warm Standby
B.Backup and Restore
C.Multi-Site Active-Active
D.Pilot Light
Correct Answer: Pilot Light
Explanation:
Pilot Light keeps the critical core of a workload active while provisioning or starting the remaining application capacity during recovery.
Incorrect! Try again.
30During a Pilot Light failover, the replicated database is ready, but the recovery application tier has not yet been deployed. Which action should normally occur before directing production traffic to the recovery Region?
Recovery architecture pattern: Pilot Light
Medium
A.Disable database replication permanently
B.Delete resources in the primary Region
C.Extend the DNS record TTL
D.Deploy and validate the application tier
Correct Answer: Deploy and validate the application tier
Explanation:
The inactive portions of a Pilot Light environment must be deployed or started and validated before production traffic is redirected.
Incorrect! Try again.
31A Pilot Light design takes too long to recover because large Amazon EC2 instances must be configured manually after every failover. Which change would most directly reduce the RTO while preserving the Pilot Light approach?
Recovery architecture pattern: Pilot Light
Medium
A.Move audit logs to S3 Glacier
B.Use tested launch templates and Auto Scaling
C.Reduce the frequency of health checks
D.Store backups for a longer retention period
Correct Answer: Use tested launch templates and Auto Scaling
Explanation:
Launch templates and Auto Scaling automate rapid creation of the application fleet, reducing provisioning time without keeping the full fleet running.
Incorrect! Try again.
32Which workload component is the best candidate to remain continuously active in the recovery Region of a Pilot Light architecture?
Recovery architecture pattern: Pilot Light
Medium
A.A full production web server fleet
B.A complete set of worker instances
C.A full production analytics cluster
D.A replicated transactional data store
Correct Answer: A replicated transactional data store
Explanation:
Pilot Light keeps critical stateful components, such as replicated databases, active while larger stateless compute fleets remain stopped or undeployed.
Incorrect! Try again.
33A retailer runs a complete but reduced-capacity copy of its application in a second Region. During a disaster, it scales out that copy and redirects all traffic to it. Which recovery pattern is being used?
Recovery architecture pattern: Warm Standby
Medium
A.Warm Standby
B.Pilot Light
C.Backup and Restore
D.Multi-Site Active-Active
Correct Answer: Warm Standby
Explanation:
Warm Standby maintains a functional, scaled-down environment that can accept traffic and expand to production capacity during failover.
Incorrect! Try again.
34A Warm Standby environment has enough capacity for only 20% of normal demand. What should the failover runbook do before sending all production traffic to that environment?
Recovery architecture pattern: Warm Standby
Medium
A.Increase DNS TTL values across both Regions
B.Scale resources and verify application health
C.Disable monitoring to reduce operational load
D.Delete the primary environment and its backups
Correct Answer: Scale resources and verify application health
Explanation:
A reduced-capacity standby should be scaled and health-checked before it receives full production demand.
Incorrect! Try again.
35A business is comparing Pilot Light with Warm Standby. It can accept higher ongoing cost in exchange for a shorter RTO. Why is Warm Standby generally more suitable?
Recovery architecture pattern: Warm Standby
Medium
A.It restores all components only from backups
B.It serves traffic from every Region continuously
C.It keeps a complete application stack running
D.It removes the need for data replication
Correct Answer: It keeps a complete application stack running
Explanation:
Warm Standby has a complete, operational environment already running at reduced capacity, so fewer components must be started during recovery.
Incorrect! Try again.
36A team periodically sends a small percentage of synthetic transactions to its Warm Standby environment. What is the primary recovery benefit of this practice?
Recovery architecture pattern: Warm Standby
Medium
C.It verifies that the standby stack remains functional
D.It eliminates the need to scale during failover
Correct Answer: It verifies that the standby stack remains functional
Explanation:
Synthetic transactions exercise the standby application's components and dependencies, helping detect recovery failures before an actual incident.
Incorrect! Try again.
37An application serves users concurrently from two AWS Regions. Route 53 directs requests to healthy endpoints based on latency. Which recovery pattern does this represent?
Recovery architecture pattern: Multi-Site (Active-Active) configurations
Medium
A.Backup and Restore
B.Multi-Site Active-Active
C.Pilot Light
D.Warm Standby
Correct Answer: Multi-Site Active-Active
Explanation:
In a Multi-Site Active-Active architecture, multiple Regions serve production traffic simultaneously and routing shifts traffic away from unhealthy endpoints.
Incorrect! Try again.
38A company is designing an Active-Active shopping cart service across two Regions. Users may update the same cart through either Region. Which issue requires the most careful design?
Recovery architecture pattern: Multi-Site (Active-Active) configurations
Medium
A.Manual creation of compute after an outage
B.Monthly backup retention and archive pricing
C.Concurrent data updates and conflict resolution
D.Delayed provisioning of the secondary VPC
Correct Answer: Concurrent data updates and conflict resolution
Explanation:
Active-Active writes can occur in multiple Regions, so the data layer must define consistency behavior and resolve conflicting updates.
Incorrect! Try again.
39Two active Regions each handle 50% of an application's normal traffic. Either Region must handle all traffic if the other fails. What capacity principle should guide the design?
Recovery architecture pattern: Multi-Site (Active-Active) configurations
Medium
A.Each Region needs only half of the production load
B.Each Region must scale to the full production load
C.The database alone must support the full load
D.The recovery Region can remain without compute
Correct Answer: Each Region must scale to the full production load
Explanation:
After one Region fails, the surviving Region must absorb the failed Region's traffic, so it needs enough available or rapidly scalable capacity for the total load.
Incorrect! Try again.
40An Active-Active application stores user session state only in the memory of regional web servers. After Route 53 moves a user to another healthy Region, the user is unexpectedly signed out. Which design change best addresses this issue?
Recovery architecture pattern: Multi-Site (Active-Active) configurations
Medium
A.Store session state in a replicated shared data layer
B.Create larger instance stores in each Region
C.Increase the DNS TTL for all application records
D.Disable health checks on regional load balancers
Correct Answer: Store session state in a replicated shared data layer
Explanation:
Replicated external session storage makes session data available across Regions and avoids dependence on a specific regional web server.
Incorrect! Try again.
41A company replicates an Amazon Aurora database to a secondary Region using an Aurora global database. During a regional failure, the secondary cluster is promoted successfully, but application recovery still exceeds the RTO because clients continue using the original database endpoint. Which design most directly resolves this orchestration gap?
AWS-native disaster recovery mechanisms and service orchestration for data durability and operational resilience
Hard
A.Place an Amazon Route 53 private record in front of the database endpoint and update it during failover
B.Create an Amazon CloudFront distribution whose origin is the active Aurora database writer endpoint
C.Store the active cluster endpoint in AWS Systems Manager Parameter Store and refresh it during each deployment
D.Increase the DNS TTL of the original Aurora writer endpoint to reduce resolver traffic during recovery
Correct Answer: Place an Amazon Route 53 private record in front of the database endpoint and update it during failover
Explanation:
A stable Route 53 private name decouples applications from Region-specific Aurora endpoints. The failover workflow can promote the secondary cluster and update the record so clients reconnect to the new writer.
Incorrect! Try again.
42A regulated workload requires immutable, logically isolated recovery points that remain available even if the production AWS account is compromised by an administrator. Which AWS-native design best satisfies this requirement?
AWS-native disaster recovery mechanisms and service orchestration for data durability and operational resilience
Hard
A.Export daily database snapshots to an encrypted S3 bucket owned by the production AWS account
B.Copy AWS Backup recovery points into a separate account vault protected by AWS Backup Vault Lock
C.Replicate EBS snapshots into another Region while retaining them in the production AWS account
D.Enable S3 Versioning in production and deny object deletion through an application IAM role
Correct Answer: Copy AWS Backup recovery points into a separate account vault protected by AWS Backup Vault Lock
Explanation:
Cross-account copies establish an isolation boundary, while Vault Lock enforces write-once-read-many retention controls. Keeping recovery points only in the compromised production account does not provide equivalent protection.
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43An application writes an order to Amazon DynamoDB and then asynchronously publishes an event. During a regional disaster, DynamoDB global tables preserve the order, but some events are missing in the recovery Region. Which redesign most effectively preserves the order-to-event relationship across failover?
AWS-native disaster recovery mechanisms and service orchestration for data durability and operational resilience
Hard
A.Use S3 Cross-Region Replication to copy application log files containing the published events
B.Use Route 53 health checks to redirect event publishers when the primary Region becomes unhealthy
C.Use EventBridge scheduled rules to scan the orders table and publish recently modified records
D.Use DynamoDB Streams and deploy an idempotent stream consumer in each participating Region
Correct Answer: Use DynamoDB Streams and deploy an idempotent stream consumer in each participating Region
Explanation:
DynamoDB Streams derives events from committed table changes, reducing the dual-write inconsistency. Idempotent consumers are necessary because stream processing and failover can produce duplicate deliveries.
Incorrect! Try again.
44A disaster recovery workflow uses AWS Step Functions to promote a database, scale compute, update DNS, and run validation. Operators may retry the workflow after a timeout whose completion state is unknown. Which property is most important for preventing retries from corrupting the recovery state?
AWS-native disaster recovery mechanisms and service orchestration for data durability and operational resilience
Hard
A.Each workflow task should use an Express Workflow to minimize orchestration execution latency
B.Each workflow task should be idempotent and verify the current resource state before changing it
C.Each workflow task should disable service API retries and immediately report transient failures
D.Each workflow task should execute concurrently so that the total recovery duration is minimized
Correct Answer: Each workflow task should be idempotent and verify the current resource state before changing it
Explanation:
An idempotent task can be repeated safely after ambiguous timeouts or partial completion. State checks also allow the workflow to resume without repeating incompatible promotion, scaling, or routing operations.
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45A 40 TiB application is rebuilt in a recovery Region from nightly snapshots. Snapshot creation meets an 8-hour RPO, but restoring storage and rehydrating application caches takes 14 hours against a 6-hour RTO. Which change addresses the violated objective without changing the backup interval?
Recovery architecture pattern: Backup and Restore
Hard
A.Move backup initiation to off-peak hours so snapshot creation causes less production contention
B.Increase backup retention from thirty days to ninety days in the secondary recovery Region
C.Pre-provision critical restored datasets or maintain a continuously replicated minimal data tier
D.Create snapshots every four hours while retaining the existing restoration and cache procedures
Correct Answer: Pre-provision critical restored datasets or maintain a continuously replicated minimal data tier
Explanation:
The failure is in recovery time, not recovery-point freshness. Pre-positioning data or moving toward a Pilot Light design reduces restore and rehydration time without altering the backup interval.
Incorrect! Try again.
46A database receives writes at an approximately uniform rate. Full backups occur every 24 hours and transaction logs are archived every 15 minutes. After a disaster, the latest usable log archive is timestamped 10:45, while the failure occurred at 10:57. Ignoring clock skew, what is the effective data-loss window?
Recovery architecture pattern: Backup and Restore
Hard
A.Approximately 24 hours 12 minutes, because logs are applied after restoring the full backup
B.Approximately 24 hours, because only the latest full backup can be considered recoverable
C.Approximately 15 minutes, because the archive schedule always determines actual loss
D.Approximately 12 minutes, because recovery can replay logs through 10:45
Correct Answer: Approximately 12 minutes, because recovery can replay logs through 10:45
Explanation:
The full backup supplies the base state, and archived logs advance it to 10:45. The unrecoverable interval is therefore minutes.
Incorrect! Try again.
47Infrastructure is recreated from AWS CloudFormation during a Backup and Restore recovery. The stack consistently fails because an S3 bucket name is globally unique and remains owned by the unavailable primary account configuration. Which design best improves deterministic recovery?
Recovery architecture pattern: Backup and Restore
Hard
A.Retain the fixed bucket name and repeatedly retry stack creation until the global namespace releases it
B.Use the primary Region name as a hard-coded suffix in every recovery environment resource identifier
C.Parameterize Region-specific names and use generated physical identifiers instead of fixed global names
D.Create the bucket manually during each disaster and remove it from the CloudFormation stack definition
Correct Answer: Parameterize Region-specific names and use generated physical identifiers instead of fixed global names
Explanation:
Recovery templates must account for global namespaces and environmental differences. Parameterized or generated names make repeated deployment into another Region predictable and avoid dependence on a fixed physical identifier.
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48A company copies encrypted Amazon RDS snapshots to a recovery Region. During a disaster exercise, the snapshots are visible but cannot be restored because the original customer-managed KMS key is unavailable in that Region. Which preparation would have prevented this failure?
Recovery architecture pattern: Backup and Restore
Hard
A.Attach an IAM policy to the snapshot that grants the recovery account permission to decrypt it
B.Enable automatic key rotation on the source KMS key before copying each database snapshot
C.Store the source KMS key identifier in Parameter Store and retrieve it during database restoration
D.Encrypt the regional snapshot copies with a usable KMS key in the destination Region
Correct Answer: Encrypt the regional snapshot copies with a usable KMS key in the destination Region
Explanation:
Encrypted recovery artifacts must reference cryptographic material usable at the recovery location. IAM access or knowledge of a source key identifier cannot substitute for an available destination key.
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49A Pilot Light environment keeps an asynchronously replicated database running in the recovery Region, while application servers are created only after a disaster. A test shows that database promotion takes 4 minutes, infrastructure deployment takes 11 minutes, instance bootstrapping takes 9 minutes, and validation takes 6 minutes. If the stages are strictly sequential, what RTO can the design realistically claim?
Recovery architecture pattern: Pilot Light
Hard
A.At least 30 minutes, excluding detection and operator decision time
B.At least 19 minutes, because promotion can be excluded from application recovery time
C.At least 26 minutes, because validation occurs after the service has already recovered
D.At least 15 minutes, because deployment and bootstrapping describe the same recovery stage
Correct Answer: At least 30 minutes, excluding detection and operator decision time
Explanation:
For sequential stages, the technical recovery duration is minutes. Detection, declaration, and human approval would increase the end-to-end RTO.
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50A Pilot Light design stores current application data in the recovery Region but creates the VPC, load balancers, IAM roles, and compute fleet only during failover. Which risk most directly threatens its RTO despite successful data replication?
Recovery architecture pattern: Pilot Light
Hard
A.DNS records may have lower TTL values than those used by the normal production environment
B.Regional service quotas or unavailable instance capacity may block rapid infrastructure expansion
C.Cross-Region data transfer charges may increase while the database replication stream remains active
D.The recovery database may contain more current records than the last primary database snapshot
Correct Answer: Regional service quotas or unavailable instance capacity may block rapid infrastructure expansion
Explanation:
Pilot Light depends on creating or scaling substantial resources during the incident. Quota limits and capacity shortages can therefore prevent the environment from meeting its tested startup time.
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51A Pilot Light architecture uses an Amazon RDS read replica in another Region. After promotion during a regional outage, the application writes to the promoted database. The original primary later returns. Which failback strategy best avoids silently discarding recovery-Region writes?
Recovery architecture pattern: Pilot Light
Hard
A.Demote the recovery database and immediately reconnect it as a read replica of the restored original primary
B.Re-enable the old replication relationship and allow timestamp ordering to resolve all divergent transactions
C.Treat the promoted database as authoritative and establish replication toward a newly prepared original Region
D.Restore the original primary from its latest local automated backup and redirect traffic without reconciliation
Correct Answer: Treat the promoted database as authoritative and establish replication toward a newly prepared original Region
Explanation:
Promotion breaks the original one-way relationship, and new writes make the datasets divergent. The active recovery database must remain authoritative until data is replicated or migrated back deliberately.
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52A company claims a 20-minute RTO for its Pilot Light design because its Auto Scaling group can launch the required instances in 12 minutes. During a test, newly launched instances cannot retrieve deployment artifacts because the artifact bucket exists only in the failed Region. What architectural principle was violated?
Recovery architecture pattern: Pilot Light
Hard
A.All application instances must remain continuously active in both Regions to qualify as Pilot Light
B.All dependencies required for scale-out must be replicated or independently available in the recovery Region
C.All Auto Scaling groups must use identical Availability Zone identifiers in both participating Regions
D.All deployment artifacts must be embedded in public AMIs that are shared with every AWS account
Correct Answer: All dependencies required for scale-out must be replicated or independently available in the recovery Region
Explanation:
A Pilot Light is recoverable only if its dormant compute tier can access code, images, secrets, configuration, and other dependencies. A Region-local artifact dependency invalidates the measured launch time.
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53A Warm Standby environment continuously handles 10% of production traffic and is sized for 20% of peak load. Scaling to full capacity takes 18 minutes, but the business RTO is 10 minutes. Which adjustment most directly aligns the architecture with the RTO?
Recovery architecture pattern: Warm Standby
Hard
A.Increase baseline standby capacity or reserve capacity so full service can be reached within 10 minutes
B.Send no normal traffic to the standby Region so its resources remain available for emergency scaling
C.Increase database backup frequency so the standby application tier scales in less than 10 minutes
D.Reduce Route 53 TTL values so the existing standby compute fleet automatically gains more capacity
Correct Answer: Increase baseline standby capacity or reserve capacity so full service can be reached within 10 minutes
Explanation:
Routing speed does not remove compute capacity limits. The standby must start larger, scale faster, or have assured capacity so it can support the required load within the RTO.
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54A Warm Standby system uses asynchronous database replication. At disaster declaration, monitoring reports a replication lag of 90 seconds. DNS failover completes in 20 seconds, and application scaling completes in 5 minutes. Which statement correctly distinguishes its recovery objectives?
Recovery architecture pattern: Warm Standby
Hard
A.The observed RPO is about 90 seconds, while technical service recovery takes at least 5 minutes
B.The observed RPO is zero, while technical service recovery equals the 90-second replication lag
C.The observed RPO is about 20 seconds, while technical service recovery takes about 90 seconds
D.The observed RPO is about 5 minutes, while technical service recovery takes about 20 seconds
Correct Answer: The observed RPO is about 90 seconds, while technical service recovery takes at least 5 minutes
Explanation:
Replication lag determines the potential data-loss window, while scaling and traffic redirection determine availability recovery. Since scaling takes longer than DNS failover, recovery takes at least 5 minutes.
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55A standby Region is running a reduced but functional application stack. Its database is current, but background workers are disabled to avoid duplicate processing. During failover, web traffic is redirected before workers are enabled, causing accepted requests to remain unprocessed. Which orchestration sequence is most appropriate?
Recovery architecture pattern: Warm Standby
Hard
A.Promote data services, enable and validate workers, scale the stack, and then redirect production traffic
B.Enable workers in both Regions, redirect production traffic, promote the replica, and then stop replication
C.Redirect production traffic, promote data services, disable workers, and then scale the application stack
D.Scale the web tier, redirect production traffic, restore the database, and then validate background workers
Correct Answer: Promote data services, enable and validate workers, scale the stack, and then redirect production traffic
Explanation:
Traffic should move only after the complete request-processing path is ready. Promotion, worker activation, validation, and capacity expansion must precede routing to avoid accepting work that cannot be completed.
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56A Warm Standby exercise succeeds under average traffic but fails at peak because the recovery Region reaches an Elastic Load Balancing quota before Auto Scaling finishes. Which testing practice would have exposed this weakness most reliably?
Recovery architecture pattern: Warm Standby
Hard
A.Run CloudFormation drift detection against the standby stacks before each software release
B.Run synthetic health checks against one standby endpoint at a constant low request rate
C.Run daily database restore tests without shifting application traffic from the primary Region
D.Run periodic full-load regional evacuation tests that include quota and scaling validation
Correct Answer: Run periodic full-load regional evacuation tests that include quota and scaling validation
Explanation:
Low-volume checks prove basic functionality but not production-scale recovery. A full-load evacuation exercise validates quotas, capacity, scaling behavior, dependencies, and routing under the expected disaster load.
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57Two active Regions accept updates to the same customer profile through DynamoDB global tables. Concurrent writes update different attributes of the same item, but one update disappears after replication convergence. Which change best reduces this conflict risk?
Recovery architecture pattern: Multi-Site (Active-Active) configurations
Hard
A.Increase the table's provisioned write capacity equally in both active AWS Regions
B.Reduce Route 53 TTL values so clients switch Regions before issuing concurrent writes
C.Model independently updated attributes as separate items and make operations idempotent
D.Use strongly consistent reads against each Region before submitting every local update
Correct Answer: Model independently updated attributes as separate items and make operations idempotent
Explanation:
Global-table conflict resolution can cause item-level concurrent updates to overwrite one another. Separating independently updated state narrows the conflict boundary, while idempotency protects retries.
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58An active-active API uses Route 53 latency-based routing across two Regions. A Region remains reachable and returns HTTP 200 responses from /health, but its dependency on a payment provider is broken, so all payment requests fail. Which health design most effectively prevents traffic from continuing to reach that Region?
Recovery architecture pattern: Multi-Site (Active-Active) configurations
Hard
A.Use a health check against the Region's static status page stored in an S3 bucket
B.Use a calculated or application-aware health check that reflects the critical payment dependency
C.Use an EC2 instance status check for one representative application server in the Region
D.Use a TCP health check against the load balancer listener with a shorter polling interval
Correct Answer: Use a calculated or application-aware health check that reflects the critical payment dependency
Explanation:
A shallow endpoint verifies reachability but not the critical transaction path. Routing health must represent whether the Region can actually perform the service for which it receives traffic.
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59An active-active application processes messages from independent regional queues. A producer retry and cross-Region rerouting can cause the same business event to appear in both queues. Which consumer design is required to preserve exactly-once business effects despite at-least-once delivery?
Recovery architecture pattern: Multi-Site (Active-Active) configurations
Hard
A.Use a shorter queue visibility timeout and increase the number of consumers in both Regions
B.Use message timestamps to discard any event received after its original regional submission time
C.Use FIFO queues with separate message-group identifiers generated independently by each Region
D.Use a globally meaningful idempotency key and persist the processing result atomically
Correct Answer: Use a globally meaningful idempotency key and persist the processing result atomically
Explanation:
Infrastructure delivery can be duplicated across retries and Regions. A shared business idempotency key plus atomic result persistence ensures duplicate deliveries do not create duplicate business effects.
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60A two-Region active-active service has independent availability probabilities of per Region for a given interval. The service remains available if at least one Region is available, and shared dependencies are ignored. What is the theoretical service availability?
Recovery architecture pattern: Multi-Site (Active-Active) configurations
Hard
A., because the availability probabilities of the two Regions are added directly
B., because both Regions must remain available for the service to be considered healthy
C., because routing cannot improve the availability of either individual Region
D., because both Regions must fail for the service to be unavailable
Correct Answer: , because both Regions must fail for the service to be unavailable
Explanation:
Each Region has failure probability . With independence, joint failure is , so availability is .
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