cross-region-replication

name	cross-region-replication
description	Cross-region replication options — ASR vs ZRS vs cross-region zonal restore

Cross Region Replication

When to use this skill

• Choosing the DR pattern
• Cost optimization for DR

Key concepts

• ASR — true VM-level DR, minutes RPO, configurable RTO.
• ZRS managed disks + backup — survives single-zone outage but not regional; backup CRR adds region survivability.
• Active-active multi-region with app-tier replication (DB-tier-led) — lowest RTO but highest cost/complexity.
• Cross-region restore from Recovery Services Vault — slower RTO, no continuous replication, cheaper.
• Pick by RTO/RPO + budget; many shops use ASR for tier-1, backup CRR for tier-2/3.

Common pitfalls

• Picking ASR for every VM when cheaper CRR fits non-critical tiers.
• Assuming ZRS = regional DR — it isn't.
• Skipping a real RTO test and discovering the gap during an incident.

References

• Microsoft Learn: search for "Cross Region Replication Azure VM" on https://learn.microsoft.com

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