The Burst Buffer Before Eviction

Telemetry data should buffer briefly before eviction. The pattern, the storage, and the tail-sampling enabling it.

The idea

Hold incoming spans for 60 seconds. Decisions about retention happen at the end of the buffer window.

Allows tail-based decisions: keep this trace if it had errors; drop if not.

Storage

Memory mostly. Spill to local disk if over capacity.

Distributed buffering: route by trace ID so all spans of a trace land on the same collector.

Trade-offs

Cost: collector memory. Sized to the buffer duration × span rate.

Latency: spans appear in the backend N seconds after their trace ends. Acceptable for most uses.