Calculation Burden: The Struggle to Capture Uptime Metrics

"Is the system up?" is a deceptively simple question that hides a Swiss mountain's worth of architectural and financial anxiety. For our high-scale SaaS, uptime isn't binary, but rather a spectrum of partial degradations, silent 4XX spikes, and mismatched customer expectations. But in the AWS ecosystem, the pursuit of perfecting our uptime metric led us on a journey where the cost and complexity of monitoring and observability rival the service itself.