On Wed Nov 12, 2008 at 01:40:52AM +0700, Igor Podlesny wrote:
> Hi!
>
> And I have one more idea: How about reversed (or offset) disk
> components? -- It's known that linear read speed is decreasing when
> reading from the beginning to end of HDD, thus leading to situation
> when reading from RAID is good at its beginning and rather poor at its
> ending. My suggestion (possibly) would make that speed almost constant
> in despite of reading position. Examples:
>
> RAID5:
>
> disk1: 0123456789
> disk2: 3456789012
> disk3: 6789012345
>
> i. .e, the disk1's chunks aren't offseted at all, and disks' 2 and 3 are.
>
> RAID0:
>
> disk1: 0123456789
> disk2: 9876543210
>
> Any drawbacks?
>
This is already implemented for RAID-10 (using 'far' copies). I don't
see it making any sense for RAID-5 or RAID-0 though - you need to read
from multiple disks anyway, so you're always going to be waiting for the
slowest one. In fact, it's more likely to be a handicap as you'll
effectively be multiplying the slow read points.
Cheers,
Robin
--
___
( ' } | Robin Hill <robin@xxxxxxxxxxxxxxx> |
/ / ) | Little Jim says .... |
// !! | "He fallen in de water !!" |
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