How EyanaSSDSim Models All of This
Tying every concept together — and how to read the paper and use the simulator.
Now that you understand the pieces, here's how they assemble into EyanaSSDSim — the simulator and the paper — and how to explore them yourself.
What the simulator actually does
EyanaSSDSim replays a workload (a synthetic pattern, or a real disk trace) through a faithful model of an SSD: a configurable flash hierarchy, an FTL with log-structured mapping, a chosen allocation scheme, and a garbage collector. It then measures the outcomes you now know matter:
- Write amplification — the headline efficiency number.
- Wear evenness — CV, Gini, and Fourier spread of erase counts.
- Behavior under different over-provisioning levels, GC policies, and workloads.
- A conventional SSD vs. a ZNS device with host-managed GC.
The point of the tool is to make invisible internal mechanics visible and measurable, so design choices (placement, OP, GC policy, ZNS) can be compared on equal footing.
Reading the paper with this background
| When the paper mentions… | Recall the post… |
|---|---|
| WAF, write amplification | The Hidden Write Tax |
| Over-provisioning / OP ratio | Spare Space |
| Greedy / cost–benefit GC | Garbage Collection |
| Allocation schemes S1–S6 | Data Placement |
| CV, Gini, Fourier / DoEC | Measuring Wear Evenness |
| Zones, host GC, hot/cold | Zoned Namespaces |
Try it yourself
Open the Live Simulator:
- Pick a trace (start with the built-in
zns_hotcold_demo.csv). - Set the geometry (Channels, Chips≥2, Dies, Planes, Blocks/plane, Pages/block).
- Watch blocks accumulate invalid pages, then get erased by GC; watch the WAF and wear curves live.
- Switch to ZNS mode, toggle hot/cold separation, and compare the write amplification.
Analogy. You've read the flight manual; now take the controls. The simulator is the flight simulator — safe to experiment, and every dial you turn maps to a concept you just learned.
In the EyanaSSDSim paper & simulator. This blog exists because the paper's own reviewers valued clarity for newcomers. If anything here helped a concept click, that's the goal — understanding first, numbers second.
Start from the top: What Is an SSD? — or jump to any topic from the list on the left.