An SRE team is designing a disaster recovery plan for an application hosted on Azure. The application's data tier uses Azure SQL Database. The business requires an RPO (Recovery Point Objective) of 5 minutes and an RTO (Recovery Time Objective) of 1 hour. Which Azure SQL Database feature is MOST appropriate for meeting these requirements?
- AActive geo-replication.
- BPoint-in-time restore with automated backups.
- CGeo-restore with automated backups.
- DFailover groups.
Show answer & explanationAnswer & explanation
Correct answer: D. Failover groups.
An RPO of 5 minutes and RTO of 1 hour are relatively stringent. Automated backups (A and B) typically offer RPOs in hours and RTOs in hours to days. Active geo-replication (C) can achieve an RPO of 5 seconds (near real-time) and an RTO of around 30 seconds, but it requires manual failover. Failover groups (D) leverage active geo-replication but add automatic failover and the ability to manage a group of databases, which perfectly aligns with the RPO of 5 minutes and RTO of 1 hour by automating the recovery process.
Why the other options are wrong
- A. Active geo-replication provides a very low RPO (5 seconds) and RTO (30 seconds), but it requires manual failover. While it meets the RPO, the question implies an automated recovery for the RTO. Failover groups build on this for automation.
- B. Point-in-time restore from automated backups typically has an RPO of minutes to hours (depending on backup frequency) and an RTO of several hours or more, not meeting the 1-hour RTO.
- C. Geo-restore uses geo-redundant automated backups, offering similar RPO to point-in-time restore (hours) and an RTO of potentially 12+ hours, significantly exceeding the requirements.
Azure SQL Failover Groups
A feature of Azure SQL Database and SQL Managed Instance that manages replication and failover of a group of databases to a secondary region, providing automatic failover capabilities and a single endpoint for application connectivity.
- Leverages Active Geo-Replication for data synchronization.
- Supports RPO in minutes (asynchronous) or seconds (synchronous, cross-zone for Hyperscale).
- Automates failover to a secondary region, reducing RTO.
- Provides a read-write and an optional read-only listener endpoint for applications.
Memory trick: SQL DR: 'Backups for slow, Geo for fast, Failover for auto-blast!'