D2FS: Device-Driven Filesystem Garbage Collection

This conference talk presents D2FS (Device-Driven Filesystem Garbage Collection), a novel mechanism that frees log-structured filesystems from performing garbage collection by leveraging the garbage collection capabilities of underlying flash storage devices. Learn about the three key components: Coupled Garbage Collection which consolidates valid flash pages both physically and logically; Migration Upcall which asynchronously notifies the host about updated file mappings with minimal interference to foreground operations; and Virtual Overprovisioning which ensures timely device-level garbage collection by separating filesystem partition size from physical storage capacity. The research demonstrates significant performance improvements, with D2FS outperforming F2FS by 3× (FIO), zoned F2FS by 1.7× (FIO), and IPLFS by 1.5× (MySQL YCSB-F). This 15-minute presentation from USENIX FAST '25 addresses a primary obstacle hindering widespread adoption of log-structured filesystems in production environments.