Abstract not found

Random redundant allocation of data to parallel disk arrays can be exploited to achieve low access delays. New algorithms are proposed which improve the previously known shortest queue algorithm by systematically exploiting that scheduling decisions can be deferred until a block access is actually

We describe and evaluate a strategy for declustering the parity encoding in a redundant disk array. This declustered parity organization balances cost against data reliability and performance during failure recovery. It is targeted at highly-available parity-based arrays for use

RAID5 performance is critical while rebuild is in progress, since in addition to the increased load to recreate lost data on demand, there is interference caused by rebuild requests. We report on simulation results, which show that processing user requests at a higher, rather than the same priority as rebuild requests, results in a lower response time for user requests, as well as reduced rebuild time. Several other parameters related to rebuild processing are also explored. 1

environment, where access to a centrally-stored CAD system is often necessary to make progress on a design project. These applications and many others mandate both high performance and high availability from their storage subsystems. Redundant disk arrays are systems in which a high level of I/O performance

Redundant disk arrays are a popular method of improving the dependability and performance of disk storage and an ever-increasing number of array architectures are being proposed to balance cost, performance, and dependability. Despite their differences, there is a great deal of commonality between

Redundant disk arrays are single fault tolerant, incorporating a layer of error handling not found in nonredundant disk systems. Recovery from these errors is complex, due in part to the large number of erroneous states the system may reach. The established approach to error recovery in disk

for public release and sale is Sv D distribution is unlimited U Abstract Another type of failure is media failure. One com-mon way to deal with this type of failure is by periodi-Redundant disk arrays provide a way for achieving cally generating archive copies of the database and by rapid recovery

Through the use of redundancy, disk arrays can be made single fault tolerant. Disk arrays which provide single fault tolerance, categorized by a taxonomy known as RAID (Redundant Arrays of Inexpensive

RAID5 tolerates single disk failures by recreating lost data blocks on demand, but this results in the doubling of the load of surviving disks for pure read workload. This increase may be unacceptable if the original load was high. Clustered RAID (CRAID) with parity group size G smaller than