IBM Netfinity ServeRAID-3H, Инструкция по установке и эксплуатации, Страница: 15 / 212

After you install the device drivers and utility programs, refer to
Chapter 5, “Starting and Using the Utility Programs” on
page 97.
Understanding RAID Technology
RAID is the technology of grouping several hard disk drives in a
computer into an
array that you can define as one or more logical
drives. Each logical drive 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
hard disk drive.
When you group multiple physical hard disk drives into a logical
drive, the ServeRAID controller can transfer data in parallel from the
multiple drives in the array. 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 work 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
impressive increase in throughput, but also a decrease in response
time. The combination of parallel transfers and simultaneous
responses to multiple requests allows disk arrays to provide a high
level of performance in network environments.
Interleave Depth and Stripe-Unit Size
With RAID technology, data is striped across an array of hard disk
drives. This data-distribution scheme complements the way the
operating system requests data.
The granularity at which data from one file is stored on one drive of
the array before subsequent data is stored on the next drive of the
array is called the
interleave depth.
You can control the interleave depth and maximize the performance
of your ServeRAID controller by setting a stripe-unit size that is close
Chapter 1. Getting Started
5