Karl Voit wrote:
> > 443: root <at> ned ~ # mdadm --examine /dev/sd[abcd] > > Shows that all 4 devices are ACTIVE SYNC.... Please note that there is no "1" behind sda up to sdd!
Yes, you're right. Seems you've created an array/superblocks on both sd[abcd] (line 443 onwards), and on sd[abcd]1 (line 66 and onward). I'm unsure why 'pvscan' says there is an LVM PV on sda1 (line 118/119). Probably it's a misfeature in LVM, causing it to find the PV inside the MD volume if the array has not been started (since it says that the PV is ~700 GB).
> Running zero-superblock on "sd[abcd]" and then assembling the array > from "sd[abcd]_1_" sounds odd to me. Well this is because of the false(?) superblocks of sda-sdd in comparison to sda1 to sdd1.
Yes ok, I missed that part of the story. In that case it sounds sane to zero the superblocks on sd[abcd], seeing that 'pvscan' and 'lvscan' finds live data that you could backup on the array consisting of sd[abcd]1.
root@ned ~ # mdadm --assemble /dev/md0 /dev/sda1 /dev/sdb1\ /dev/sdc1 /dev/sdd1 mdadm: cannot open device /dev/sda1: Device or resource busy mdadm: /dev/sda1 has no superblock - assembly aborted
Odd message. Does "lsof | grep sda" show anything using /dev/sda(1)?
I should have mentioned that I did not use the whole hard drive space for sd[abcd]1. I thought that if I have to replace one of my Samsungs with another drive that has not the very same capacity, I'd better use exactly 250GB partitions and forget the last approx. 49MB of the drives.
Good idea.
The problem seems to be the superblocks.
Which ones, those on sd[abcd]1 ? You've probably destroyed them by syncing the array consisting of sd[abcd].
Can I repair them?
No, but you can recreate them without touching your data. I think the suggestion from Andreas Gredler sounds sane. I'm unsure if hot-adding a device will recreate a superblock on it. Therefore I'd probably run --create on all four devices and use sysfs to force a repair, instead of (as Andreas suggests) creating the array with one 'missing' device. Do remember to zero the superblocks on sd[abcd] first, to prevent mishaps... - 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
