DR / Passive Secondary — Official Microsoft Position

The Windows Server 2022 Licensing Guide (official PDF) explicitly states:

"A Windows Server license is not required for the disaster recovery server if the Hyper-V role within Windows Server is used to replicate virtual OSEs from the production server at a primary site to a disaster recovery server."

✅ Conditions that must be met:
• Replicated VMs must not be running on the DR server except during actual failover or DR testing
• DR server must not be in the same cluster as the production server
• DR server may only run Hyper-V, receive replication, test failover, and await failover — nothing else

✅ SQL Server passive instance (with SA): No additional SQL licence required for a truly passive failover instance. Without SA, SQL must be licensed on the DR node.

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💡 Recommendation — even though no licence is strictly required, consider:

Option A — Rely on DR rights (lowest cost): No WS licence needed. Works well if the DR server is truly passive and you can demonstrate compliance if audited. SA not required for WS DR rights.

Option B — Licence the DR host anyway: Full peace of mind. Removes any audit risk. Lets you use the DR host for dev/test without restrictions. Recommended for organisations with regular compliance reviews.

Option C — Add Software Assurance: Cleanest compliance story — explicitly covers both WS and SQL passive rights, plus SA benefits (new version rights, Azure Hybrid Benefit, etc.). Best value if you're also licensing SQL on the DR node.