Namhyung Kim <namhyung@xxxxxxxxx> writes: > 2011-06-15 (ì), 08:51 +0200, Keld JÃrn Simonsen: >> On Wed, Jun 15, 2011 at 11:02:00AM +0900, Namhyung Kim wrote: >> > If @conf->far_offset > 0, there is only 1 stripe so that we can treat >> > the array same as 'near' arrays. >> >> does it also work with more than 2 copies - eg 3 copies? >> I think the original code just takes the available data blocks with the >> lowest address. >> > > Hi, > > Let me clarify this: AFAIK, 'far offset' array saves redundant data in > the diagonally adjacent chunk/disk, so it could be roughly thought as > 'raid0' array with reduced size - just ignore redundant chunks here. It > was my mistake considering it as 'near' array. :( > I'm confused again. If fo > 0 && fc > 1 && nc > 1 then it turns out to a near array with reduced size, no? Does it still need to be treaded as RAID0? > Therefore, it makes more sense distributing reads over the array based > on some criteria - here, the address of starting sector - like RAID0 > does. Now I see that the same goes to the 'far copies' array exactly, so > the original code is correct. > > Thanks. -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
