zonefs: Mapping POSIX File System Interface to Raw Zoned Block Device Accesses

The zonefs file system is a simple file system that exposes zones of a zoned block device (host-managed or host-aware SMR hard-disks and NVMe ZonedNamspace SSDs) as files, hiding from the application most zoned block device zone management and access constraints. The zonefs file system is intended as a simple solution for use cases where raw block device accesses from the application have been considered a better solution. This talk will present zonefs features, with a focus on how the rich POSIX file system-call interface is used to seamlessly implement the execution of zoned block device specific operations. In particular, the talk will cover zonefs changes to seamlessly accommodate the new NVMe Zoned Namespace (ZNS), such as number of active zones, the time zones can remain in the active state, and the new Zone Append command. The talk will conclude with an example use of zonefs with the key-value store application LevelDB, showing the advantages in term of code simplicity over raw block device file accesses. Performance results with LevelDB as well as with synthetic benchmarks are also shown.

Learning Objectives

Zoned block devices principles,zonefs file systems,Zoned block device use cases,NVMe ZNS