| Summary: | 碩士 === 國立成功大學 === 工程科學系 === 86 === Video servers are much interesting in recent research. For
astorage subsystem of video servers it a common target to
getmore performance and more serviced users. Addition to
theimprovement of hard disk itself, disk array and RAID can
bothimprove the performance of storage subsystem. But the
mostserious defect of parallel disks is the low reliability.
Twoways to compensate the reliability of parallel disks
areparity check and data replication. Due to the nature of
videoservers, real-time requirement, we use data replication
toimprove disk array reliability.A characteristic when video
servers operates, like KTV or videocassette renting, is that
people often instruct part of hugemovie database, and it means
that different movie has differentpopularity. Most recent
researches about storage subsystem ofvideo servers ignore this
fact and assume all movies the sameprobability to be accessed.
It wastes kinds of system resourceto treat movies with low
popularity as popular ones because wemust use more resource to
compensate reliability of highlyaccessible movies.In this
thesis, it is considered that fact of differentpopularity of
movies. We vary the striping degree and numberof copies for each
movie according to its popularity to havebetter resource
utility. We would discuss some problems aboutdata striping and
replication and then proposed a method todecide movie striping
degree and number of copies. Finallysimulation results verified
our ideas.
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