The Design of Large-Scale, Do-It-Yourself RAIDs

In this paper we explore the design of "Do-It-Yourself" RAIDs: RAID systems that can assembled by the end user from commercially available disks, enclosures, cables, racks, computers, and networks. We quantitative- ly evaluate the tradeoffs in cost, performance, and reliability of these DIY-RAID systems. Our principal result is an architecture that scales from 10s to 1000s of disks; we demonstrate that a 1995 implementation would have much lower cost, better and more scalable performance, and roughly the same reliability as commercial- ly available hardware RAID systems. Furthermore, if current trends continue, these DIY-RAIDs will replace near-line tape libraries within a few years.