A backup (lesson 5.5) brings back yesterday's data. But if a whole region fails, the booking portal of Nordlicht Reisen GmbH, a fictional travel agency, should keep running in a second location, and soon. That is what Azure Site Recovery is for. The exam calls this: configure Azure Site Recovery for Azure resources and perform a failover to a second region.
Prior knowledge: Regions, zones, and paired regions are explained in "AZ-900 compact", lesson 2.1; redundancy and availability are in lesson 3.5, Azure Backup in lesson 5.5. This lesson is about replicating a machine to another region.
Backup or Site Recovery?
| Azure Backup | Azure Site Recovery | |
|---|---|---|
| Purpose | bring data back (errors, deletion, malware) | continue operation after an outage (disaster case, business continuity) |
| How | recovery points in a vault | continuous replication of the disks to a second region |
| Result | restored data or a newly created VM | VM created in the target region from a recovery point |
| Vault | Recovery Services vault or Backup vault | Recovery Services vault |
Site Recovery is part of the strategy for business continuity and disaster recovery (BCDR): it coordinates replication, failover, and recovery of Azure VMs and on-premises machines. It does not replace a backup, and a backup does not replace replication. The terms RPO (how much data loss is acceptable) and RTO (how long it may take) determine what you need.