Tech Due Diligence OPS-4: Uptime and SLA Management

Define and publish SLA or SLO targets that fit your market. Common SaaS benchmarks: 99.9% (roughly 8.7 hours downtime per year) for standard tiers, 99.95% (roughly 4.4 hours) for enterprise tiers, 99.99% (roughly 52 minutes) for mission-critical services. Make sure your architecture can actually deliver the number before you commit to it.

Set up external uptime monitoring with services like Pingdom, UptimeRobot, Better Uptime, or Datadog Synthetics. External monitoring catches issues that internal tools miss - network path problems, DNS failures, and similar. Monitor key user-facing endpoints, not just infrastructure health checks.

Publish uptime history on a public status page. This shows transparency and gives customers a historical record of your reliability. Include current service status, incident history, and uptime metrics.

Design for high availability at the infrastructure level. Deploy across multiple availability zones. Use load balancers to distribute traffic and handle server failures. Implement auto-scaling for traffic spikes. Use managed database services with automatic failover. Set up health checks that remove unhealthy instances automatically.

Build reliability into the application itself. Implement graceful degradation so core functionality keeps working when non-critical components fail. Add circuit breakers to prevent cascade failures. Use retry logic with exponential backoff for transient errors. Consider chaos engineering to proactively find reliability weaknesses.

Track and report SLA compliance regularly. Calculate uptime monthly and annually. Investigate any month that falls below target. Develop and share action plans to prevent recurrence.

Adopt error budgets. If your SLO is 99.9%, your error budget is 0.1% downtime per month. When the budget is healthy, prioritise features. When it is depleted, prioritise reliability. This gives you a data-driven way to balance the two.