Compaq 108164-003 - ProLiant - 800 Technical Manual page 29

I/O Performance Tuning of Compaq Servers
Figure 17.
environment. These results were obtained using Iometer version 1998.10.08, Copyright 1998 by Intel
Corporation. Intel does not endorse any Iometer results.
In Figure 17, the x-axis indicates the number of drives on the SCSI bus. The eight marks between
each number indicate the number of blocks transferred in a single input/output (I/O) (1, 2, 4, 8,
16, 32, 64, and 128 blocks of data, respectively). One block is 512 bytes. Write caching is
disabled. Queuing is simple with 16 tagged commands
Figure 18.
obtained using Iometer version 1998.10.08, Copyright 1998 by Intel Corporation. Intel does not
endorse any Iometer results.
Figures 19 and 20 illustrate the additional performance gains associated with 10K RPM drives.
Figure 19 shows the decrease in latency for both read and write operations.While Figure 20
exhibits the increased throughput for client requests.
ECG044.0399
Sequenti a l Read: 2% Sequenti a l Wri t e: 1%
1400
1200
Representati v e Compaq 7,200-rpm dri v e
Compaq 10k-II dri v e
1000
800
600
400
200
0
1 2
Composite performance of 10k-II drives and 7,200-rpm drives in a typical server
Sequential Read: 2% Sequential Write: 1% Random Read: 58% Random Write: 39%
50
40
30
Representative Compaq 7,200-rpm drive
20
Compaq 10k-II drive
10
0
-10
1 2
Percent improvement calculated using values from Figure 17. These results were
Composite Performance
Random Read: 58% Random Wri t e: 39%
3 4 5
Number of Drives/Block Count
.
Composite Performance
3 4 5
Number of Drives/Block Count
W i t h l a rger bl o ck si z es, the SCSI
bus will saturate, limiting the I/O rate
6
7
6 7
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