On Sat, 13 Oct 2012, Piergiorgio Sartor wrote:
I've a RAID-6, 10 HDDs, which, due to some hardware issue, has lost 4 HDDs. The RAID cannot be assembled anymore, of course. The missing HDDs are now available and sane, so I guess it could be possible to force an assemble operation. What would be the reccomended way to proceed? mdadm -A /dev/md1xx --force -c mdadm.conf and then re-add the missing HDDs (does the above works?)
Just --assemble --force if they all disappeared at roughly the same time (so all drives have not too different event count). If one drive has a very different event count, leave it out of the assembly and add it later.
Or to re-create the array with "assume-clean" and with the proper device order? The device role seems to be available using "mdadm -E /dev/sdXy", I assume this gives the proper order.
Re-creating a raid5/6 with --assume-clean is for me a disaster recovery, something that should be performed when everything else fails. It's extremely unfortunate that a lot of guides bring this in very early in the fault finding process. I've talked to several people who completely screwed up their arrays by getting it wrong here.
-- Mikael Abrahamsson email: swmike@xxxxxxxxx -- 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
