BetrFS

Summary

The B^ε-tree File System, or BetrFS, is an in-kernel file system that uses B^ε-trees to organize on-disk storage. B^ε-trees are a write-optimized dictionary, and offer the same asymptotic behavior for sequential I/O and point queries as a B-tree. The advantage of a B^ε-tree is that it can also ingest small, random writes 1-2 orders of magnitude faster than B-trees and other standard on-disk data structures. The goal of BetrFS is to realize performance that strictly dominates the performance of current, general-purpose file systems.

News

• Our SODA 2020 paper shows how to limit tail-latencies in amortized data structures like B^ε-trees.
• Our FAST 2020 paper extends BetrFS to support efficient copy-on-write clones of files and directories.
• Our OSDI 2020 paper describes our verified implementation of a B^ε-tree.
• Our SPAA 2020 paper explains how we extend the DAM model to more precisely model hard disks and SSDs, and the implications for data-structure design.