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Technical Report Details

Date 27-5-2003
Number DISI-TR-03-06
Title Providing Single I/O Space and Multiple Fault Tolerance in a Distributed RAID
Authors Alessandro Di Marco, Giovanni Chiola, Giuseppe Ciaccio
Bibtex Entry @techreport{DRAIDreport, author = {A. Di Marco AND G. Chiola AND G. Ciaccio}, title = {{Pro
E-mail ciaccio@disi.unige.it
Link ftp://ftp.disi.unige.it/person/CiaccioG/draid_techrep.ps.gz
Abstract Commodity EIDE disks provide low cost storage but are severely limited in bandwidth and cannot be made fault-tolerant. On the other hand, conventional RAID devices provide reliability and performance but worse price/performance figures. A cluster of PCs can be seen as a collection of networked low cost disks; such a collection can be operated by proper software so as to provide the abstraction of a single, larger block device. By adding suitable data redundancy, such a disk collection as a whole could act as single, highly fault tolerant, virtual RAID device, providing capacity and reliability along with the convenient price/performance typical of commodity clusters. Such a distributed RAID could even be accessible by each of the stations in the cluster, rather than throughout one or few end-points, with a potentially higher aggregate I/O bandwidh and better suitability to parallel I/O. The overall picture is a prototype of a so-called ``I/O-centric cluster'', namely, a cluster of PCs offering storage services under a Single I/O Space (SIOS), rather than offering traditional computing power. This paper reports about the design and performance of a prototype of such a virtual RAID system, called DRAID, on a Gigabit Ethernet cluster of PCs.
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