Characterizing and Emulating FDP SSDs with Warp
Published in 24th USENIX Conference on File and Storage Technologies (FAST '26), 2026
Recommended citation: Inho Song, Shoaib A. Qazi, Javier González, Matias Bjørling, Sam H. Noh, and Huaicheng Li. "Characterizing and Emulating FDP SSDs with Warp." In Proceedings of the 24th USENIX Conference on File and Storage Technologies (FAST '26), Santa Clara, CA, USA, February 2026. https://www.usenix.org/system/files/fast26-song.pdf
Inho Song, Shoaib A. Qazi, Javier González, Matias Bjørling, Sam H. Noh, and Huaicheng Li. 24th USENIX Conference on File and Storage Technologies (FAST ‘26).
Abstract
Flexible Data Placement (FDP) promises to reduce write amplification by steering writes across reclaim unit handles (RUHs), yet outcomes vary widely across devices. We present Warp, the first open emulator and comprehensive study of FDP SSDs. A cross-device, cross-workload characterization shows that FDP sustains near-1 WAF when RUH isolation aligns with object lifetimes, but fails under misclassification, RUH interference, or adversarial invalidations. Warp reproduces hardware WAF trends while exposing per-RUH dynamics and configurable policies hidden in real devices. We use Warp to explore the firmware design space for FDP and to demonstrate policies that reduce WAF beyond current hardware — combining empirical characterization with a transparent emulator to advance FDP research from anecdotal reports to principled understanding.