Overview
Write Amplification by Engine across Real Traces
What it shows. WAF for all nine engine variants — Conventional (block & superblock GC), FDP (single / PI / II placement), and ZNS (single & hot/cold with greedy or cost-benefit GC) — on each real trace.
How to read it. Lower is better (less write amplification). Grouped bars let you compare engines within a workload and the same engine across workloads. Note that no single engine wins everywhere: placement schemes help on skewed, reused data but can cost extra on write-once or uniform workloads (see Placement Effect).
What we found
- No universal winner. On the aged prxy_1_3M trace the best is FDP-II (1.01), then FDP-PI (1.06) and conventional block (1.07); ZNS variants are highest (1.49–1.75).
- Write-once workloads (TPC-C, sequential) sit at WAF 1.00 for every in-place engine — no rewrite means no GC. Only ZNS hot/cold pays migration there (1.67–1.76).
- Short, bursty prxy_1 is the hardest: ZNS hot/cold blows up to 2.89–3.11, while conventional block stays 1.35.
