On Mon Nov 16, 2009 at 08:38:34AM -0800, Christopher Chen wrote:
> On Mon, Nov 16, 2009 at 8:31 AM, Robin Hill <robin@xxxxxxxxxxxxxxx> wrote:
> > On Mon Nov 16, 2009 at 04:26:32PM +0100, Goswin von Brederlow wrote:
> >
> >> What I'm aiming at is that offset might better fit into erase blocks,
> >> cause less internal fragmentation on the disk and give better wear
> >> leveling. Might improve speed and lifetime. But that is just a
> >> thought. Maybe test and do ask Intel (or other vendors) about it.
> >>
> > I very much doubt this will make any difference. With SSDs you have to
> > throw out any preconceptions of internal layout you may have. You have
> > absolutely no idea (or control of) where two consecutive blocks will
> > actually get written. Fragmentation and seek time are thus irrelevant
> > (or uncontrollable anyway).
> >
> > I don't see how any RAID-10 layout would perform better than another
> > with SSDs, unless there's internal optimisations/constraints which
> > affect sequential reading from multiple devices. I'm not aware of any
> > though - RAID-10 n2 may be the same layout as RAID-1 but it's an
> > entirely separate piece of code.
>
> Don't forget that RAID-1 also does balanced reads.
>
Only for parallel reads. A single sequential read will only access a
single disk, whereas I believe for RAID-10 it will access both disks.
Cheers,
Robin
--
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( ' } | Robin Hill <robin@xxxxxxxxxxxxxxx> |
/ / ) | Little Jim says .... |
// !! | "He fallen in de water !!" |
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