Hard drive short stroking fun – Part 2

Hard drive short stroking fun – Part 2

Continued from Part 1, my testing of WD 640GB Caviar Black hard drives continues! 

I configured 2x 640GB hard drives in Raid-0 to see for myself how they would perform on a regular onboard motherboard raid controller.  I tested the drives at full capacity and then tested them at 10% capacity (Short Stroking).  To do this, I used the Intel Storage software to create a new Raid-0 with a 128k stripe size then ran the tests.  Next I deleted the Raid-0 array and re-created it with the same settings only this time I specified the Intel software to only use 10% of the total capacity.

The Results:

2x 640GB WD WD6401AALS Raid-0 - HD Tune Pro Read Benchmark

All of the speeds increased significantly once the drives were configured for Raid-0.  All of the speeds were approximately double the speed of the single drive, which was what I expected.  The average access time stayed the same as well.

2x 640GB WD WD6401AALS Raid-0 Short Stroke 128GB - HD Tune Pro Read Benchmark

Through short stroking, the speeds became much more consistent with the Average transfer speed increasing by 20 MB/s to 173.5 MB/s.  The access time also dropped to 7.4 ms which was the same as it was with just a single drive.

The final variation of my short stroking tests was to use the same WD 640GB Caviar Black hard drives only this time configure a Raid-0 array with 4 of them.  Once again, I tested the drives at full capacity, then I ran the tests again with the array short stroked to 10% capacity.  This time I also decided it would be a fun idea to enable the Intel controllers Write Caching feature even though I don’t have the system on a UPS, what’s there to lose!  

The Results:

4x 640GB WD WD6401AALS Raid-0 - HD Tune Pro Read Benchmark

With 4 640GB hard drives all working together I would’ve expected better results!  A 45 MB/s increase with 2 more hard drives isn’t very impressive at all!  More speed is more speed but at the cost of price, heat & power, I’m not certain I would ever bother with a 4 disk Raid-0 setup.  Hopefully short stroking the drives has more significant results.

4x 640GB WD WD6401AALS Raid-0 Short Stroke 256GB - HD Tune Pro Read Benchmark

Yuck!! A 2 MB/s increase!  At 90% less capacity than what is available on the array I would’ve expected the speed to go up more than that.  At least the Access Time of 7.4 ms is consistent…

4x 640GB WD WD6401AALS Raid-0 Short Stroke 256GB Write Cache Enabled - HD Tune Pro Read Benchmark

WOAH! There’s the speed.  I enabled the write cache for previous tests without much performance gain but this time it really shines.  I didn’t test the 4 disk Raid-0 at full capacity which I think I may have to do, it would be interesting to see if the speeds are as high.

That’s all for now.