Storage Elements Overview; Physical Hard Drives; Arrays - HP StorageWorks 4000s - NAS Administration Manual

Storage Elements Overview

The NAS server offers optimized performance for a growing environment. Storage capacity
can increase as a business grows without downtime or compromised performance. Storage
limitations are based on the type of SAN the NAS server is connected to. See the individual
SAN documentation for limitations of Windows Storage Server 2003.
Preliminary physical storage management tasks involve managing:
Drive array concepts and data protection methods, including fault tolerance options are
discussed in this section. This information will help guide decisions on how to best configure
the arrays.

Physical Hard Drives

For personal or small business use, the capacity and performance of a single hard drive is
adequate. However, larger businesses demand higher storage capacities, higher data transfer
rates, and greater security from data loss if drives fail.
Merely adding extra drives to the system increases the total storage capacity, but has little
effect on the system efficiency, because data can only be transferred to one hard drive at a time.
Figure 24
Figure 24: Separate physical drive (P1, P2, P3) read/write (R/W) operations

Arrays

With an array controller installed in the system, the capacity of several physical drives can be
logically combined into one or more logical units called arrays. When this is done, the
read/write heads of all the constituent physical drives are active simultaneously, dramatically
reducing the overall time required for data transfer.
NAS 4000s and 9000s Administration Guide
Physical Hard Drives
Arrays
Logical Drives (LUNs)
illustrates the read/write process with separate physical hard drives.
P1
R/W
P2 P3
Storage Management Overview
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