On 25/06/2009 12:07, NeilBrown wrote: [...]
stripe-width is only really needed on raid4/5/6 as it is aimed at avoiding read-modify-write, so it would be the stripe size, which would be minimum_io_size.
[...]
stride-size is used for raid0 or raid4, or the "Asymmetric" raid5 layouts. It allows ext3 to stagger which drive certain 'hot' data structures are on. The current metrics don't allow for that at all. I'm not saying they should, and I'm not sure how they could. But it is sad.
Even sadder, when a raid 0/4/5/6 is reshaped over more discs (and probably other scenarios outwith md), both stripe-width and stride-size change. Is there any prospect this new stacking could give us the opportunity to tell our client (LVM, filesystem, whatever) about the change, or that they'll be able to take advantage of it?
Cheers, John. -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
