On Sat, Feb 15, 2014 at 5:04 PM, Mikael Abrahamsson <swmike@xxxxxxxxx> wrote: > On Sat, 15 Feb 2014, Jon Nelson wrote: > >> Out of 12 drives, I thought RAID6 only offered a total of *2* failed >> devices. It seems to me that you have 7 devices in sync and 4 *almost* in >> sync. It's this "almost" part that has me confused. How can the raid run if >> the event count doesn't match? Wouldn't at least 10 out of 12 drives have to >> have the same event count to avoid data loss? > > > Correct. When you use --assemble --force you're basically telling mdadm "I > know what I'm doing and I'll take the risk of data loss or corruption". If > you assemble in with a kicked drive that was kicked long ago that has a > really far off event count, you can really really screw things up. > > Unless you use --force, mdadm won't assemble an array where the event count > doesn't match up. Aha. So if you ran a check in this case, it would find some number of blocks that don't match up. What does MD do in that case? -- Jon -- 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
