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Zorluk: KolayHigh Availability and Disaster Recovery Design

An organization is designing a disaster recovery (DR) strategy for an internal reporting application. The application is non-critical, and the business has set both the Recovery Time Objective (RTO) and the Recovery Point Objective (RPO) to 24 hours. The primary objective of the design is to minimize ongoing running costs. Which disaster recovery strategy should the solutions architect recommend to meet these requirements?

  1. A
    Multi-Site Active-Active strategy by running full-capacity environments in two regions with continuous bidirectional database replication.
  2. B
    Warm Standby strategy by running a scaled-down duplicate of the application and database in a secondary region to allow rapid failover.
  3. Backup and Restore strategy by taking daily snapshots of the database and application data, storing them in Amazon S3, and recreating the resources only when a disaster occurs.Cevap
  4. D
    Pilot Light strategy by keeping a minimal copy of the database replication instance running continuously in a secondary region while keeping application servers turned off.

Cevap

Backup and Restore strategy by taking daily snapshots of the database and application data, storing them in Amazon S3, and recreating the resources only when a disaster occurs.
A Backup and Restore strategy is the most cost-effective option because it does not require running active infrastructure in a secondary region under normal operations. Backups can be scheduled daily to satisfy the 24-hour RPO, and the infrastructure can be provisioned on-demand (e.g., using CloudFormation or Terraform) to restore the application within the 24-hour RTO limit.

Adım Adım Çözüm

1
Analyze the RTO and RPO requirements.
The target recovery time (RTO) is 24 hours, and the allowed data loss window (RPO) is 24 hours.
This determines which DR strategy is technically viable. High availability or active replication is not required for a 24-hour window.
2
Evaluate the cost constraint.
Ongoing running costs must be minimized.
This rules out active-passive or active-active strategies that require running compute or database instances in a secondary region continuously.
3
Select the matching DR strategy.
Backup and Restore is selected since backups can be taken daily (RPO = 24 hours) and restored within 24 hours (RTO = 24 hours) without running standby resources.
It achieves the lowest possible cost by keeping no resources running in the secondary region until a disaster is declared.

Anahtar Kavram

Disaster Recovery strategies trade off RTO/RPO against cost, where Backup & Restore has the lowest cost and highest RTO/RPO.
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