ZoneBuffer: An Efficient Buffer Management Scheme for ZNS SSDs

The introduction of Zoned Namespace SSDs (ZNS SSDs) presents new challenges for existing buffer management schemes. In addition to traditional SSD characteristics such as read/write asymmetry and limited write endurance, ZNS SSDs possess unique constraints, such as requiring sequential writes within each zone. These features make conventional buffering policies incompatible with ZNS SSDs. This paper introduces ZoneBuffer, a novel buffering scheme designed specifically for ZNS SSDs. ZoneBuffer's innovation lies in two key aspects. First, it introduces a new buffer structure comprising a Work Region and a Priority Region. The Priority Region is further divided into a clean page queue and a zone cluster of dirty pages. By confining buffer replacement to the Priority Region, ZoneBuffer ensures optimization for ZNS SSDs. Second, ZoneBuffer incorporates a lifetime-based clustering algorithm to group dirty pages within the Priority Region, optimizing write operations. Preliminary experiments conducted on a real ZNS SSD demonstrate the effectiveness of ZoneBuffer. Compared with conventional schemes like LRU and CFLRU, the results indicate that ZoneBuffer significantly improves performance.