Edge Cache and CDN Platform · View 24 of 29 · 6 · Operations
Decisions
- Availability is measured from outside. The 99.99% SLI is the success rate seen by probes in twelve networks that are not ours, not the success rate in our own logs.
- Absence of traffic pages. A black-holed PoP shows no errors from the inside, so a PoP serving less than 20% of its request rate for the same hour last week is treated as an incident.
- Prometheus runs in every PoP with 15 days of local retention, so a PoP cut off from the core can still be diagnosed through out-of-band access.
Per path pattern
- Hit ratio, byte hit ratio, stale-served ratio and refusal counts are published per path pattern as well as per property and PoP. A bad key only shows up at that level.
Numbers
- Delivery SLO 99.99% monthly across the anycast set; purge API 99.95%; configuration control plane 99.9%. Single-PoP availability is deliberately not a target.
