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Is there a 2.5" HDD that is built such that it behaves like RAID 0 (IE, improved performance). If not, is there software (firmware) that allows one to do that?

clarity: I'm thinking of something where a hard disk would be split in two equal partitions, and then it behaves like a RAID 0. This is to avoid idle platters and read/write heads during peak time.

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Learn about Raid...en.wikipedia.org/wiki/RAID –  Moab Jan 3 '11 at 15:50
    
@moab check my edit –  Tshepang Jan 3 '11 at 15:56
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I think it might help to completely understand how hard drives access data and function physically to help answer why your idea would not work. en.wikipedia.org/wiki/Hard_drives The heads cannot split apart or move independently. –  Troggy Jan 3 '11 at 16:23
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@ Tshepang.."Redundant Array of Independent Disks" see the "Independent Disks" part? It does not say independent partitions. –  Moab Jan 3 '11 at 16:47
    
@moab I understand that RAID refers to multiple disks. That's why I said behaves like and offered clarity. –  Tshepang Jan 3 '11 at 17:54

4 Answers 4

up vote 7 down vote accepted

Hard disks do not "split"; most have only a single array of heads which will have to swing back and forth between the different sections of the disk therefore reducing the drive to the speed of an abacus. Your energy is better spent looking at technology improvements instead of trying to be clever.

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+1 Try a good SSD, like the OCZ Vertex or others. –  Chris S Jan 3 '11 at 21:10

If you only use a portion of your HDD, you will get faster access times (since on average, the head doesn't have to move as to seek to the data you want). Transfer times will be slightly faster on average as well, as transfer speed slows down.

See this article for a detailed explanation.

Here's a benchmark:

alt text

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This is commonly known as short-stroking. As the graph shows, it works, but you've got to really restrict it in order to get a significant performance increase. Buying a better drive generally gives a much greater performance boost. –  afrazier Jan 3 '11 at 21:17
    
you wanna fix the first sentence for grammar –  Tshepang Jan 4 '11 at 2:15
    
Sorry, I accidentally a whole word from that sentence. –  davr Jan 6 '11 at 0:06

The hard drive does not know or care about RAID. the Hard drive controller is the one that deals with RAID. All of our RAID drives in our servers are 2.5", but they are SCSI.

You will need to check if your hard drive controller supports Raid 0. (note, raid 0 is very, very risky, if you need performance bad enough, you might want to consider getting an SSD drive.) Our laptops here have Intel 25-M SSD's, that are about 5 times faster than the 7200RPM 2.5" drives we used to use in our laptops.

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check my edit; I added some info –  Tshepang Jan 3 '11 at 15:57
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That will not work. You will get no additional speed out of the drive. if you have support for AHCI, you should turn that on, as it optimizes reads a bit smarter. –  Brian Jan 3 '11 at 16:12

Basically, it doesn't matter what the partition arrangement is - you can't do something like "stripe writes across multiple partitions" on a single disk to get a speedup. There's still only one read head on one arm. That's your speed limit - everything else is superfluous. The only way to get more speed is more heads, hence more drives. (Or just move to SSDs, of course)

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