Redundant array of independent disk (RAID) is the technology of grouping several physical drives in a computer into a disk group that you can define as one or more logical devices. Each logical device appears to the operating system as a single drive. This grouping technique greatly enhances logical-drive capacity and performance beyond the physical limitations of a single physical drive.
When you group multiple physical drives into a logical device, the controller can transfer data in parallel from the multiple drives in the disk group. This parallel transfer yields data-transfer rates that are many times higher than with nonarrayed drives. This increased speed makes the system better able to meet the throughput (the amount of data processed in a given amount of time) or productivity needs of the multiple-user network environment.
The ability to respond to multiple data requests provides not only an increase in throughput, but also a decrease in response time. The combination of parallel transfers and simultaneous responses to multiple requests enables disk arrays to provide a high level of performance in network environments.
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