On Thu, Mar 11, 2010 at 3:25 AM, Asdo <asdo@xxxxxxxxxxxxx> wrote: > Neil Brown wrote: >> >> I am pleased to announce the availability of >> mdadm version 3.1.2 >> >> [CUT] >> >> Significant changes are: >> - The default metadata has change again (sorry about that). >> It is now v1.2 and will hopefully stay that way. [CUT] >> > > I remember some discussion about alignment for 1.1 and 1.2: is it possible > on 1.2 to guarantee alignment of RAID device on the physical devices? > 4K alignment would be needed on SSDs and 2TB disks w/ 4k physical 512b > logical emulation. Actually on SSDs the alignment could be even more than > 4k, I am not sure. > Should we bypass the defaults and put 1.0 metadata on those? > What was the downside of 1.0 so that it was not made default? > > Thanks for your great job > -- > 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 > 1.0 puts the metadata at the end. You run in to situations where various tools that detect what's inside of a block device get confused about if it's an md member, or whatever's been stuffed inside of md (and is thus stored at the front) instead. What would be nice would be the ability to specify a non-default alignment unit and a reference sector in the backing device to use for the start of alignment. However I don't think anyone who's really needed it has yet seen fit to provide a patch. Presuming someone did want to write a patch, is the above outlined pair of options desirable as the solution, and what sort of long/short names might be used? -- 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
