HighLight: Using a Log-structured File System for Tertiary Storage Management

13 years 5 months ago

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Robotic storage devices offer huge storage capacity at a low cost per byte, but with large access times. Integrating these devices into the storage hierarchy presents a challenge to ﬁle system designers. Log-structured ﬁle systems (LFSs) were developed to reduce latencies involved in accessing disk devices, but their sequential write patterns match well with tertiary storage characteristics. Unfortunately, existing versions only manage memory caches and disks, and do not support a broader storage hierarchy. HighLight extends 4.4BSD LFS to incorporate both secondary storage devices (disks) and tertiary storage devices (such as robotic tape jukeboxes), providing a hierarchy within the ﬁle system that does not require any application support. This paper presents the design of HighLight, proposes various policies for automatic migration of ﬁle data between the hierarchy levels, and presents initial migration mechanism performance ﬁgures. This research was sponsored in part by t...

John T. Kohl, Carl Staelin, Michael Stonebraker

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