On 19 January 2011 02:44, NeilBrown <neilb@xxxxxxx> wrote: > On Tue, 18 Jan 2011 22:59:07 +0700 Igor Podlesny <for.poige+linux@xxxxxxxxx> > wrote: Hi Neil! Thanks for your reply. > 1/ The rationale given by Greg for non-power-of-two chunk sizes is not so > Ârelevant for Linux I think. ÂThe more common filesystems Âcan be told that > Âthe device is a RAID and can deliberately offset the extra super blocks so > Âthey don't all end up on the one device. Yeah, that's right. But "non-2^n"-stripe is simpler in general and wouldn't require any additional "tuning" and hopes, that FS' developers took into consideration such things as possible RAID below FS- or even FS/LVM-2-layer. Shorter speaking, it would give benefits in a much more simpler way. Also, there's another problem with "2^n": stripe size are "gaped" more and more: 512, 1024, 2048, 4096. I'd rather try using something like 768, 1355, 1719. Unable at present though... > > 2/ Power-off-two is required simply because it was easier to code. ÂThe I guessed that. :-) > Ârestriction was dropped for RAID0 a year or more ago. ÂThe restriction > Âcould be dropped for RAID4/5/6 and RAID10 relatively easily. ÂIt would just > Ârequire a thorough code review and changing a few 'mask' and 'shift' > Âoperations to divisions. [...] Would be really great. Really! -- End of message. Next message? -- 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
