B-trees, Shadowing, and Range-Operations

B-trees are used by many file-systems to represent files and directories. They provide guarantied logarithmic time key-search, insert, and remove. Shadowing, or copy-on-write, is used by other file-systems to implement snapshots, crash-recovery, write-batching and RAID. Serious difficulties arise when trying to use b-trees and shadowing in a single system.

This paper is about a set of b-tree algorithms that respect shadowing and achieve good concurrency. These algorithms were used in an experimental object-disk. We believe that this work is applicable not only to object-disks but also to other file-systems.

By: Ohad Rodeh

Published in: H-0248 in 2006


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