Large payload buffering drives up Envoy memory consumption

Envoy buffers headers and may buffer request/response bodies depending on configuration. When services exchange large payloads without proper streaming, Envoy buffers entire payloads in memory, driving up consumption. Indicated by downstream_rq_rx_buf_flood or upstream_rq_tx_buf_flood metrics.

Check buffer flood metrics. If streaming large bodies, ensure streaming is properly configured to prevent Envoy from buffering entire payloads in memory.