Compaq 108164-003 - ProLiant - 800 White Paper page 21

ECG025.0997
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HITE APER
(cont.)
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In Figure 10, our tests show that if you require 24 Gigabytes of storage capacity the
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performance gain of 33% is in using twelve 2GB disks instead of six 4GB disks. With
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concurrency taking place by using multiple lower capacity drives (twelve 2GB drives),
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more requests are being processed; thus improving performance. However, consider the
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limitations of this configuration. By having twelve lower capacity drives, you are limiting
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the maximum disk capacity on that controller.
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20,000,000
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18,000,000
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16,000,000
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14,000,000
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12,000,000
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10,000,000
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8,000,000
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6,000,000
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4,000,000
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2,000,000
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0
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4
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. . Figure 10: Like Capacity Scaling in a RAID 0 Environment.
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Similar test results were found in our RAID 5 environment. Again, when scaling (or using
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more drives) in an environment, the like capacity test shows a 54% performance increase
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when using eight 2GB drives versus four 4GB drives, as shown in Figure 11.
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21
Like Capacity Scaling (RAID 0 - 1 Controller)
8 16 20 24 28
Number of Clients
33%
32 36 40 44 48
12 x 2GB
6 x 4GB
3 x 9GB
52 56 57