Efficient Data Placement for Zoned Namespaces (ZNS) SSDs

ZNS SSDs (Zone Namespaces SSDs) are a new type of SSDs. It allows the entire SSD space to be divided into multiple zones, and only sequential writes are allowed within each zone. ZNS SSDs effectively improve the read/write throughput of SSDS and reduce write magnification. However, the sequential write and zone partitioning of ZNS SSDs pose challenges to existing storage allocation strategies. In this paper, we propose a new ZNS SSD-aware data placement algorithm. Specifically, the inserted and modified data is placed according to the lifetime of the data, and the variance of the data lifetime in each zone is used for management and garbage collection based on the calculation of the conventional garbage collection strategy. Experiments show that the lifetime-based insertion algorithm has a great improvement in stability compared with the average insertion and polling insertion algorithm, and the time performance is slightly reduced due to the calculation overhead of the lifetime. The lifetime variance-aware garbage collection algorithm is 9% better than the conventional garbage collection algorithm in terms of time performance and is more stable.