name: sla-design description: Compose Azure VM SLAs — single-VM, AS, AZ, multi-region

Sla Design

When to use this skill

• Architecture review
• SLA commitment to a customer

Key concepts

• Single VM with Premium/Ultra SSD OS+data: 99.9% connectivity SLA.
• 2+ VMs in an AS: 99.95%.
• 2+ VMs across AZs: 99.99%.
• Multi-region: composite SLA is product of per-region SLAs, but you also need active-active or active-passive design with traffic steering.
• Stateful tiers determine end-to-end SLA — your VMs may be 99.99% but the DB SLA may be the ceiling.

Common pitfalls

• Quoting compute SLA without acknowledging dependent service SLAs.
• Assuming multi-region = additive — it's multiplicative with steering overhead.
• Single Premium-SSD VM SLA only applies with all disks Premium/Ultra.

References

• Microsoft Learn: search for "Sla Design Azure VM" on https://learn.microsoft.com

Validation-first: verify every Azure fact against the Microsoft Learn MCP server (cite the Learn URL); Learn overrides built-in knowledge. If no Learn MCP server is configured, flag the answer ⚠️ unverified and mark specs as indicative. Analysis only — verify against Microsoft documentation before applying.