RAID 1 and Non-RAID Hard Drive Performance Comparison using tiobench
Here is a RAID 1 partition (500GB Seagate & 2TB WD):
Sequential Reads
File Blk Num Avg Maximum Lat% Lat% CPU
Identifier Size Size Thr Rate (CPU%) Latency Latency >2s >10s Eff
---------------------------- ------ ----- --- ------ ------ --------- ----------- -------- -------- -----
2.6.27-16-generic 1792 4096 1 86.46 25.43% 0.044 1498.90 0.00000 0.00000 340
2.6.27-16-generic 1792 4096 2 145.66 86.49% 0.042 1629.59 0.00000 0.00000 168
2.6.27-16-generic 1792 4096 4 156.01 186.7% 0.074 2226.75 0.00044 0.00000 84
2.6.27-16-generic 1792 4096 8 200.13 471.4% 0.130 1519.34 0.00000 0.00000 42
Random Reads
File Blk Num Avg Maximum Lat% Lat% CPU
Identifier Size Size Thr Rate (CPU%) Latency Latency >2s >10s Eff
---------------------------- ------ ----- --- ------ ------ --------- ----------- -------- -------- -----
2.6.27-16-generic 1792 4096 1 2.15 2.529% 1.817 92.54 0.00000 0.00000 85
2.6.27-16-generic 1792 4096 2 3.03 3.873% 1.665 69.56 0.00000 0.00000 78
2.6.27-16-generic 1792 4096 4 4.89 8.890% 2.292 159.16 0.00000 0.00000 55
2.6.27-16-generic 1792 4096 8 4.85 20.62% 4.840 263.46 0.00000 0.00000 24
Sequential Writes
File Blk Num Avg Maximum Lat% Lat% CPU
Identifier Size Size Thr Rate (CPU%) Latency Latency >2s >10s Eff
---------------------------- ------ ----- --- ------ ------ --------- ----------- -------- -------- -----
2.6.27-16-generic 1792 4096 1 21.36 25.66% 0.177 5462.31 0.00109 0.00000 83
2.6.27-16-generic 1792 4096 2 23.07 63.22% 0.301 7352.31 0.00109 0.00000 36
2.6.27-16-generic 1792 4096 4 23.78 161.6% 0.631 4570.67 0.00305 0.00000 15
2.6.27-16-generic 1792 4096 8 20.13 278.8% 1.406 6773.69 0.00763 0.00000 7
Random Writes
File Blk Num Avg Maximum Lat% Lat% CPU
Identifier Size Size Thr Rate (CPU%) Latency Latency >2s >10s Eff
---------------------------- ------ ----- --- ------ ------ --------- ----------- -------- -------- -----
2.6.27-16-generic 1792 4096 1 0.11 0.092% 0.017 0.07 0.00000 0.00000 118
2.6.27-16-generic 1792 4096 2 0.10 0.181% 0.019 0.07 0.00000 0.00000 57
2.6.27-16-generic 1792 4096 4 0.11 0.468% 0.023 0.11 0.00000 0.00000 23
2.6.27-16-generic 1792 4096 8 0.10 0.609% 0.027 13.54 0.00000 0.00000 16
Here is a non-RAID 1 partition:
Non-RAID 2TB 64MB WD
File Blk Num Avg Maximum Lat% Lat% CPU
Identifier Size Size Thr Rate (CPU%) Latency Latency >2s >10s Eff
---------------------------- ------ ----- --- ------ ------ --------- ----------- -------- -------- -----
2.6.27-16-generic 1792 4096 1 119.20 33.15% 0.032 240.85 0.00000 0.00000 360
2.6.27-16-generic 1792 4096 2 109.59 65.63% 0.069 802.35 0.00000 0.00000 167
2.6.27-16-generic 1792 4096 4 112.27 122.8% 0.127 659.32 0.00000 0.00000 91
2.6.27-16-generic 1792 4096 8 110.35 234.3% 0.270 952.49 0.00000 0.00000 47
Random Reads
File Blk Num Avg Maximum Lat% Lat% CPU
Identifier Size Size Thr Rate (CPU%) Latency Latency >2s >10s Eff
---------------------------- ------ ----- --- ------ ------ --------- ----------- -------- -------- -----
2.6.27-16-generic 1792 4096 1 2.30 1.236% 1.697 419.69 0.00000 0.00000 186
2.6.27-16-generic 1792 4096 2 2.03 2.395% 3.469 903.90 0.00000 0.00000 85
2.6.27-16-generic 1792 4096 4 1.63 3.803% 6.019 2352.58 0.05000 0.00000 43
2.6.27-16-generic 1792 4096 8 1.57 7.796% 14.564 2342.62 0.17500 0.00000 20
Sequential Writes
File Blk Num Avg Maximum Lat% Lat% CPU
Identifier Size Size Thr Rate (CPU%) Latency Latency >2s >10s Eff
---------------------------- ------ ----- --- ------ ------ --------- ----------- -------- -------- -----
2.6.27-16-generic 1792 4096 1 55.37 62.93% 0.068 2175.37 0.00022 0.00000 88
2.6.27-16-generic 1792 4096 2 61.63 158.7% 0.119 3028.74 0.00044 0.00000 39
2.6.27-16-generic 1792 4096 4 62.15 338.7% 0.223 3053.16 0.00174 0.00000 18
2.6.27-16-generic 1792 4096 8 62.34 757.1% 0.434 2561.85 0.00153 0.00000 8
Random Writes
File Blk Num Avg Maximum Lat% Lat% CPU
Identifier Size Size Thr Rate (CPU%) Latency Latency >2s >10s Eff
---------------------------- ------ ----- --- ------ ------ --------- ----------- -------- -------- -----
2.6.27-16-generic 1792 4096 1 1.42 1.093% 0.017 0.07 0.00000 0.00000 130
2.6.27-16-generic 1792 4096 2 1.32 1.927% 0.018 0.16 0.00000 0.00000 69
2.6.27-16-generic 1792 4096 4 1.06 3.132% 0.020 0.12 0.00000 0.00000 34
2.6.27-16-generic 1792 4096 8 1.26 9.106% 0.028 13.84 0.00000 0.00000 14
Conclusion
On average RAID 1 does increase sequential read speeds by 50%. It also decreases sequential write speeds by more than 50% as well, which is obviously bad.
Random Writes suffer big time, .11MB/sec vs 1.42MB/sec.
RAID 1 is great where read performance is important, but write performance is severely affected.
Tags:
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