HD Doctor Logo

DR: AWS vs Azure vs On-Premise

By the HD Doctor Technical Team

Direct answer

Choosing DR architecture defines whether your company comes back in 4h or 4 days after incident. AWS, Azure and on-prem have specific trade-offs. This comparison shows technical and financial criteria by size and workload.

Three fundamental DR architectures

(1) On-prem DR at secondary site: infrastructure duplication at another data center/server room. Higher capex cost, lower failover latency. (2) AWS DR (CloudEndure, AWS Backup, AWS Elastic Disaster Recovery): VM and data replication. Pay-per-use during active DR. (3) Azure DR (Azure Site Recovery, Azure Backup): similar to AWS, integrated with Microsoft 365 and Active Directory. Each has optimal scenario.

Comparison by critical dimension

  1. 1.
    Typical monthly cost (50 TB, 20 VMs). On-prem: hardware ~US$ 50,000-150,000 capex + ~US$ 2,000/month operation. AWS Elastic DR: ~US$ 800-2,500/month (replication only, no active VMs). Azure Site Recovery: ~US$ 700-2,300/month similar. Cost varies 10× or more.
  2. 2.
    Typical achievable RTO. On-prem: 1-4h if secondary site ready. AWS/Azure: 1-12h depending on documented failover plan. Without active DR: 24-72h or more.
  3. 3.
    Operational complexity. On-prem: high — requires team operating two sites. AWS: medium — advanced automation but requires cloud expertise. Azure: medium-high — good if environment already Microsoft.
  4. 4.
    Replication latency. On-prem (same city): < 5ms. AWS/Azure: 50-200ms for same region, 200-500ms inter-regional. Impact: some OLTP workloads feel it; web/application doesn't.
  5. 5.
    Data compliance. On-prem: 100% control over location. AWS/Azure: depends on chosen region — São Paulo region for Brazil, Virginia/Ireland for others. LGPD/GDPR/HIPAA has specific requirements.

FAQ

For SMB of 10-50 employees, which to recommend?

Typically AWS Elastic DR or Azure Site Recovery. Cost is fraction of on-prem (no capex). RTO 4-8h meets most needs. Initial migration in 1-2 months with consulting.

Does on-prem DR still make sense in 2026?

Yes for: (1) companies with strong regulatory restriction (government, sensitive healthcare); (2) very large volumes (PB+) where cloud transfer is prohibitively expensive; (3) workloads with < 5ms inter-site latency requirement.

AWS vs Azure: which to choose?

Main criterion: where rest of infrastructure is. 100% Microsoft environment (Active Directory, SQL Server, Office 365): Azure has better integration. Heterogeneous or already in AWS: stay in AWS. Technical DR difference is smaller than ecosystem difference.

How to combine cloud DR with immutable backup?

Recommended: on-prem production + immutable backup on S3 Object Lock + active DR via AWS Elastic DR or Azure Site Recovery. Three layers defend against diverse failures.

Want to design DR architecture for your company?

Technical + financial analysis + wave-based implementation plan.

Next reads