Microsoft Certified: DevOps Engineer ExpertImplement a Site Reliability Engineering (SRE) strategyHard
A financial services company is implementing a disaster recovery (DR) strategy for its critical trading platform hosted on Azure. The platform requires extremely low RTO (Recovery Time Objective) and RPO (Recovery Point Objective), ideally measured in seconds or very few minutes. They need a strategy that maintains a fully functional, up-to-date replica of the production environment in a secondary region, ready to take over immediately with minimal data loss. Which DR strategy would best meet these requirements?
- AWarm Standby
- BActive-Active (Hot Standby)
- CPilot Light
- DBackup and Restore
Show answer & explanationAnswer & explanation
Correct answer: B. Active-Active (Hot Standby)
An Active-Active (Hot Standby) strategy involves running identical, fully provisioned instances of the application in multiple regions, often with active traffic routing to both. This configuration provides the lowest RTO and RPO, as a failover requires only redirecting traffic, meeting the 'extremely low RTO and RPO' requirement.
Why the other options are wrong
- A. Warm Standby keeps a pre-provisioned, scaled-down replica, which still requires scaling up and potentially some configuration before taking full load, thus higher RTO/RPO than active-active.
- C. Pilot Light involves replicating data and a minimal set of core infrastructure, requiring provisioning and scaling up during failover, leading to higher RTO/RPO than active-active.
- D. Backup and Restore has the highest RTO and RPO as it involves restoring from backups, which is too slow for the stated requirements.
Active-Active (Hot Standby) DR
A disaster recovery strategy where identical, fully provisioned application instances run simultaneously in multiple regions, ready to handle traffic immediately.
- Offers the lowest RTO and RPO (seconds/minutes).
- Highest cost due to duplicate infrastructure.
- Can distribute live traffic across regions for load balancing and redundancy.
Memory trick: DR Strategies: How fast can you get back online and how much data can you lose?