Logic MegaRAID Express User's Guide

MegaRAID Express 500 Hardware Guide
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Optimizing Data Storage
Data Access Requirements
Each type of data stored in the disk subsystem has a different frequency of read
and write activity. If you know the data access requirements, you can more successfully
determine a strategy for optimizing the disk subsystem capacity, availability, and
performance.
Servers that support Video on Demand typically read the data often, but write data
infrequently. Both the read and write operations tend to be long. Data stored on a general-
purpose file server involves relatively short read and write operations with relatively
small files.
Array Functions
You must first define the major purpose of the disk array. Will this disk array increase the
system storage capacity for general-purpose file and print servers? Does this disk array
support any software system that must be available 24 hours per day? Will the
information stored in this disk array contain large audio or video files that must be
available on demand? Will this disk array contain data from an imaging system?
You must identify the purpose of the data to be stored in the disk subsystem before you
can confidently choose a RAID level and a RAID configuration.
Planning the Array Configuration
Answer the following questions about this array:
Question Answer
Number of physical disk drives in the array
Purpose of this array. Rank the following factors:
Maximize drive capacity
Maximize the safety of the data (fault tolerance)
Maximize hard drive performance and throughput
How many hot spares?
Amount of cache memory installed on MegaRAID Express 500
Are all of the disk drives and the server protected by a UPS?