Re: [Lsf-pc] [LSF/MM TOPIC] really large storage sectors - going beyond 4096 bytes

Chris Mason
2014-01-22T20:13:20Z

On Wed, 2014-01-22 at 11:50 -0800, Andrew Morton wrote:
> On Wed, 22 Jan 2014 11:30:19 -0800 James Bottomley <James.Bottomley@hansenpartnership.com> wrote:
>
> > But this, I think, is the fundamental point for debate. If we can pull
> > alignment and other tricks to solve 99% of the problem is there a need
> > for radical VM surgery? Is there anything coming down the pipe in the
> > future that may move the devices ahead of the tricks?
>
> I expect it would be relatively simple to get large blocksizes working
> on powerpc with 64k PAGE_SIZE. So before diving in and doing huge
> amounts of work, perhaps someone can do a proof-of-concept on powerpc
> (or ia64) with 64k blocksize.

Maybe 5 drives in raid5 on MD, with 4K coming from each drive. Well
aligned 16K IO will work, everything else will about the same as a rmw
from a single drive.

-chris