Conquest: Better Performance Through a Disk/Persistent-RAM Hybrid File System

An-I Andy Wang , Peter Reiher , and Gerald J. Popek
UCLA, The Laboratory for Advanced Systems Research

Geoffrey H. Kuenning
Harvey Mudd College


The rapidly declining cost of persistent RAM technologies prompts the question of when, not whether, such memory will become the preferred storage medium for many computers. Conquest is a file system that provides a transition from disk to persistent RAM as the primary storage medium. Conquest provides two specialized and simplified data paths to in-core and on-disk storage, and Conquest realizes most of the benefits of persistent RAM at a fractional cost of a RAM-only solution. As of October 2001, Conquest can be used effectively for a hardware cost of under $200.

We compare Conquest's performance to ext2, reiserfs, SGI XFS, and ramfs, using popular benchmarks. Our measurements show that Conquest incurs little overhead compared to ramfs. Compared to the disk-based file systems, Conquest achieves 24% to 1900% faster memory performance, and 43% to 96% faster performance when exercising both memory and disk. (full paper in html)


An-I Andy Wang, Geoffrey H. Kuenning, Peter Reiher, Gerald J. Popek. Conquest: Better Performance Through a Disk/Persistent-RAM Hybrid File System. Proceedings of the 1st USENIX Conference on File and Storage Technologies (FAST), Monterey, January 2002.

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