What are cloud SLAs and why they matter

Short answer

An SLA is a contractual commitment from a cloud provider regarding service availability, performance, and support.

How it works

• Uptime is expressed as a percentage (e.g., 99.9% = ~8.7 hours downtime/year).
• If the provider fails to meet the SLA, customers may receive service credits.
• SLAs often exclude scheduled maintenance and force majeure events.

Example

A 99.99% SLA means less than 53 minutes of downtime per year. Mission-critical apps may require multi-region active-active architectures to exceed any single SLA.

Why it matters

SLAs set expectations and provide recourse, but they do not guarantee perfection. Design architectures that do not rely solely on a single provider's SLA.