Comment by kmxdm

Yes, GC should be smart enough to free up space from padding. But then there's a write amplification penalty and meeting endurance specifications is impossible. A padded write already carries a write amplification >1, then GC needs to be invoked much more frequently on top of that to drive it even higher. With pathological Flush usage, you have to pick your poison. Run out of space, run out of SSD life.