eZNS: An Elastic Zoned Namespace for Commodity ZNS SSDs


Jaehong Min and Chenxingyu Zhao, University of Washington; Ming Liu, University of Wisconsin-Madison; Arvind Krishnamurthy, University of Washington


Emerging Zoned Namespace (ZNS) SSDs, providing the coarse-grained zone abstraction, hold the potential to significantly enhance the cost-efficiency of future storage infrastructure and mitigate performance unpredictability. However, existing ZNS SSDs have a static zoned interface, making them in-adaptable to workload runtime behavior, unscalable to underlying hardware capabilities, and interfering with co-located zones. Applications either under-provision the zone resources yielding unsatisfied throughput, create over-provisioned zones and incur costs, or experience unexpected I/O latencies.

We propose eZNS, an elastic-zoned namespace interface that exposes an adaptive zone with predictable characteristics. eZNS comprises two major components: a zone arbiter that manages zone allocation and active resources on the control plane, a hierarchical I/O scheduler with read congestion control, and write admission control on the data plane. Together, eZNS enables the transparent use of a ZNS SSD and closes the gap between application requirements and zone interface properties. Our evaluations over RocksDB demonstrate that eZNS outperforms a static zoned interface by 17.7% and 80.3% in throughput and tail latency, respectively, at most.

OSDI '23 Open Access Sponsored by
King Abdullah University of Science and Technology (KAUST)

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@inproceedings {288623,
author = {Jaehong Min and Chenxingyu Zhao and Ming Liu and Arvind Krishnamurthy},
title = {{eZNS}: An Elastic Zoned Namespace for Commodity {ZNS} {SSDs}},
booktitle = {17th USENIX Symposium on Operating Systems Design and Implementation (OSDI 23)},
year = {2023},
isbn = {978-1-939133-34-2},
address = {Boston, MA},
pages = {461--477},
url = {https://www.usenix.org/conference/osdi23/presentation/min},
publisher = {USENIX Association},
month = jul

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