Summary: Improving Storage System Availability with D­GRAID
Muthian Sivathanu, Vijayan Prabhakaran,
Andrea C. Arpaci­Dusseau, and Remzi H. Arpaci­Dusseau
Computer Sciences Department
University of Wisconsin, Madison
{muthian, vijayan, dusseau, remzi}@cs.wisc.edu
Abstract
We present the design, implementation, and evaluation of
D­GRAID, a gracefully­degrading and quickly­recovering
RAID storage array. D­GRAID ensures that most files
within the file system remain available even when an un­
expectedly high number of faults occur. D­GRAID also
recovers from failures quickly, restoring only live file sys­
tem data to a hot spare. Both graceful degradation and
live­block recovery are implemented in a prototype SCSI­
based storage system underneath unmodified file systems,
demonstrating that powerful ``file­system like'' function­
ality can be implemented behind a narrow block­based
interface.
1 Introduction

Source: Arpaci-Dusseau, Remzi - Department of Computer Sciences, Department of Computer Sciences, University of Wisconsin at Madison
Liblit, Ben - Department of Computer Sciences, University of Wisconsin at Madison

Collections: Computer Technologies and Information Sciences