A Free-Space Adaptive Runtime Zone-Reset Algorithm for Enhanced ZNS Efficiency.

While the state-of-the-art runtime zone-reset algorithm of the ZenFS in RocksDB is optimized for the performance of Zone Namespace (ZNS) SSDs, it does not take into account the lifetime constraint of ZNS SSDs. To address this issue, we present FAR, a Free-space Adaptive Runtime Zone-Reset algorithm for ZenFS, which dynamically adjusts the frequency of runtime zone-reset calls based on the available free-space in the ZNS SSD. We developed FAR with the ZenFS of RocksDB using a ZNS SSD prototype based on the Cosmos+ OpenSSD platform and compared it with the state-of-the-art runtime zone-reset algorithm used in ZenFS. Our extensive evaluations demonstrate that FAR improves the lifetime of ZNS SSD by 2x without compromising performance.