Zoned Namespace (ZNS) SSDs are gaining traction for eliminating in-device GC and enabling application-aware data management. BlobDB, an enhanced RocksDB with key-value separation, reduces compaction overhead but suffers from the GC over GC (GoG) problem, causing redundant data copying during BlobDB’s GC and Zone Cleaning (ZC). To address this, this paper proposes Same-Victim GC, aligning the victims and sizes of both GCs. Specifically, we introduce the BlobDB-Aware Zone Allocation (BAZA) algorithm to allocate blob files by creation order, eliminate victim file mismatch between two GCs, and $Z_{-} C u t o f f$ to minimize BlobDB’s GC size without additional overhead. Implemented in ZenFS v2.14 and RocksDB v7.4, our solution eliminates valid data copying, doubles compaction performance, and improves space utilization by $1.28 \times$.

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.