Quartz 5

azure-site-recovery

Properties2
tagsdisaster-recovery, site-recovery, replication
aliasesSite Recovery, ASR, disaster recovery

3 min read

Azure Site Recovery

What it is

Azure Site Recovery (ASR) is Azure’s disaster-recovery service for supported machines and workloads. It replicates them from a primary location to a secondary location and helps orchestrate test failovers, failovers, and failback. During a real outage, it can create or bring up recovery VMs from replicated data according to the recovery plan; it is not simply a set of historical backups.

Why it exists

Backup (the distinction) protects against data loss but doesn’t keep your app running. Site Recovery protects against region/site downtime — when the primary location is unavailable, you fail over to the replica and keep serving users with minimal downtime (RTO) and data loss (RPO).

Key ideas

  • Site Recovery can replicate supported Azure VMs between regions and supported on-premises machines to Azure or a secondary site. Support and prerequisites vary by scenario.
  • Continuous replication reduces the gap between the primary and recovery copy, but the recovery design still has an RPO and RTO. It does not promise zero data loss or instant recovery for every workload.
  • A test failover validates the plan without disrupting primary replication. A failover brings the recovery workload into service; failback returns it after the primary location is ready.
  • A recovery plan can order a multi-tier application’s failover and include automation or manual steps. Network, DNS, identity, dependencies, and traffic switching must be planned alongside VM replication.

Northwind example

Northwind replicates its legacy connector VM from its primary Azure region to a recovery region. During a scheduled drill, it performs a test failover into an isolated test network, confirms the connector can reach required dependencies, and records the recovery time. If the primary region fails, the recovery plan brings up the connector in the secondary region and Northwind switches the necessary traffic. Its customer data still needs its own backup and storage-redundancy design.

Common confusion

  • Site Recovery is not a backup service; Azure Backup protects point-in-time recovery copies.
  • Replication does not automatically make an application reachable. Traffic routing, DNS, permissions, and dependencies need a documented failover plan.
  • A secondary recovery configuration is not proven until a test failover succeeds and the business validates the result.

How it fits (diagram)

When to choose it

Use Site Recovery when a supported workload needs a designed recovery location and orchestrated failover for a site or region outage. Pair it with tested backups for deletion, corruption, and retention needs.

azure-backup · recovery-services-vault · azure-vm · azure-backup-policy · redundancy-lrs-zrs-grs · northwind-traders-case-study

📘 Source: Microsoft Learn — About Azure Site Recovery, checked 2026-09-16.

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