LightNVM: The Linux Open-Channel SSD Subsystem


Matias Bjørling, CNEX Labs, Inc. and IT University of Copenhagen; Javier Gonzalez, CNEX Labs, Inc.; Philippe Bonnet, IT University of Copenhagen


As Solid-State Drives (SSDs) become commonplace in data-centers and storage arrays, there is a growing demand for predictable latency. Traditional SSDs, serving block I/Os, fail to meet this demand. They offer a high-level of abstraction at the cost of unpredictable performance and suboptimal resource utilization. We propose that SSD management trade-offs should be handled through Open-Channel SSDs, a new class of SSDs, that give hosts control over their internals. We present our experience building LightNVM, the Linux Open-Channel SSD subsystem. We introduce a new Physical Page Address I/O interface that exposes SSD parallelism and storage media characteristics. LightNVM integrates into traditional storage stacks, while also enabling storage engines to take advantage of the new I/O interface. Our experimental results demonstrate that LightNVM has modest host overhead, that it can be tuned to limit read latency variability and that it can be customized to achieve predictable I/O latencies.

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@inproceedings {202260,
author = {Matias Bj{\o}rling and Javier Gonzalez and Philippe Bonnet},
title = {LightNVM: The Linux Open-Channel {SSD} Subsystem},
booktitle = {15th {USENIX} Conference on File and Storage Technologies ({FAST} 17)},
year = {2017},
isbn = {978-1-931971-36-2},
address = {Santa Clara, CA},
pages = {359--374},
url = {},
publisher = {{USENIX} Association},