What you can't forget: exploiting parallelism for zoned namespaces

This paper discusses the main benefits of ZNS and shows why ZNS can be deprived of internal parallelism when downsizing its zone writable capacity. To this end, we use two production ZNS SSDs and quantitively analyze the performance degradation caused by inter-zone interference. We then suggest a simple mechanism to detect zone-to-zone relationships generating the interference and schedule I/O requests by being aware of internal parallelism. Our evaluation results using real production ZNS devices show that our mechanism can improve the bandwidth and latency of Linux's multi-queue I/O scheduler by 1.98 × and 2.2 ×, respectively.