U-Frog

Overview

U-Frog is a Kioxia RocksDB plugin that uses io_uring to bypass the file system and send Flexible Data Placement (FDP) placement directives directly to the device, driving drive write amplification factor (WAF) to essentially 1.0. Presented by Kioxia Senior Fellow Rory Bolt at the 2025 OCP Global Summit, it is published open source and was updated to add multi-drive striping for performance. In testing it lifted RocksDB query throughput from roughly 8,000 queries per second with FDP disabled to roughly 15,000 with it enabled, while total WAF (including RocksDB compaction and file-system metadata) fell dramatically but stayed above 1.0 even as the drive itself reached ~1.0.