How to Short Stroke for RAID

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Mechanical hard drives are still the slowest part of our computers.  While SSDs are becoming more popular, not many can afford them.  Those who still like to pay about 10 cents per gigabyte will continue to buy mechanical-type hard drives. That said; let’s get right into the meat and potatoes of this article. All mechanical hard drives have a performance curve. The outer edge being the fastest and the inner edge being the slowest.  When we run a program called HD tach, we can determine the fastest part of the drive. The drives performance ranges from around 130MB/s to around 60MB/s, depending on the drive. Short stroking is grabbing the fastest part of the drive and using it for booting only. HD tach lets us find the sweet spot, or the fastest part of the drive.

Sweet spots

Sweet spots

Look at the image above. (It’s a WD3000HLFS 300gig VelociRaptor) From this picture we can determine that the ultimate sweet spot for this drive is around the 32gig location and at about the 55gig location would be the sweet spot with more space, just with a slightly slower access time.  55 x 2 is 110gig boot drive (about 102gig formatted), plenty of space for a boot drive for any OS.  By doing this (short stroking) we can use the fastest part of the drive for incredible boot times. I have started a list of drives for RAID 0 short stroking. You can do up to 6 drives in RAID 0 using the ICH10R chip. However, by going to a fourth drive in RAID 0 you add higher latency. That may be overlooked due to the data throughput of the RAID array. Three drives in RAID 0, seems to be the sweet spot. Short stroking 3 drives in RAID 0 would be  utterly incredible!

List of drives submitted by members

List of drives submitted by members

In the RAID firmware (Control+I for Intel), you’ll need to setup a RAID 0 array using all of the same type drives.  Earlier I noted that 55 gig would be the sweet spot for the above drive.  If this were three 300gig drives, it should say 839 gig. Remove it and put 165. Since it is RAID 0, it will use 55 gig of each drive.  Save the settings and confirm.  Now start installing Windows7 or whatever your favorable flavor is, and enjoy your new found speed!

How to setup RAID video

Short stroke testing of three 80 gig drive in RAID 0.

To help continue my spreadsheet, please send your HD TACH submissions to:

screen-shots (at) joeteck.com

I will determine the sweet spot for you and enter it in this spreadsheet for future viewing.  Or if you would like to submit it on the forum, there is an ongoing thread about this here. Thank you for your help.

Joeteck

Update (1:30PM EST 12/15/09): Here’s a screenshot of the performance Joeteck obtained by short stroking:

2 Velociraptors Hard Disks in Raid 0, 64GB Slice, Write-back Cache On, ICH7R Matrix RAID Controller

2 Velociraptors Hard Disks in Raid 0, 64GB Slice, Write-back Cache On, ICH7R Matrix RAID Controller

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Discussion
  1. so basically you have to find the "sweet spot" with hd tach for a single drive...

    then once thats obtained we put in raid 0...

    i have another question though..

    how do i know if i set raid to work at 8kb/16/32/64/128kb?

    i have 4 drives that i'd like to use in raid 0.... but if 3 will yeild better preformance... then 3 it is...

    currently i have 4 - wd re4 raid edition 500gb in raid 0....... and my hd tune graph looks like 2 mountans... hitting peaks of 333mb/s ... and lowest points at about 175mb/s///

    my goal is over 300mbs which is reasonable ... ...

    could you guys give any recommendations?

    .... great description on short stroke btw!

    thanks
    I am looking for some advise for my systems. I want to have some Redundancy in my HDD setup and performance, So I am thinking of using RAID 5. I want to Short Stroke 2 WD Black 1 TB HDD's and use this as the system drive. Then I planned on using another 2 1 TB drives for storage. I am not sure if I should setup a second RAID for the Storage portion or just leave the drives alone.

    Also when short stroking the HDD's, would you do this before you install Windows? This is what I want to do but I am not sure from what I have been reading, no one says when you would implement the Short Stroke. Or do you install windows then install the program to short stroke the drives and then reinstall windows on the short stroked drives as a clean copy?

    Then would you Short Stroke a 1TB to 300 GB or 100 GB? I was wanting to Short stroke them to 250 GB each but after reading this article, and the sweet spots seem to be at 100 and 300 GB I wasnt sure if I should just go with one of those.

    I would appreciate any help and advise on this. Thank you :attn:
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