Re: RAID-1 to RAID-5 online migration?
On Mon, 13 Sep 2004 15:39, Adrian 'Dagurashibanipal' von Bidder
<avbidder@fortytwo.ch> wrote:
> While I really substantiate my assumtption, Russel's right, in theory: in
> RAID1, you *do* have 2 disks, so reading 2 independent files *should* be
> possible without too much seeking.
>
> But OTOH you might run into disk scheduler issues that way, I really was
> thinking about reading one file.
In either case disk scheduler improvements could dramatically increase
performance. Improving the performance for the case of a single file without
hurting performance for other situations is difficult. Improving performance
for reading two files should not be really difficult (as far as kernel coding
projects go).
> Ok, I should finally learn not to open my mouth too wide where I don't have
> the experience, so I guess I'll stay silent in this thread now.
No need to do that, just do the tests. Setting up a test-bed for these things
should only take a few hours if you have some spare hardware. As I
previously noted things MAY have changed since I last tested this area of
performance. This is why I never claimed you to be wrong, I just requested
benchmark results to support your assertions. I've done the tests of early
2.4.x kernels to show the opposite of what you say, but things could have
improved since.
--
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