On Sat, Jul 15, 2017 at 7:26 PM, Andreas Klauer <Andreas.Klauer@xxxxxxxxxxxxxx> wrote: > On Sat, Jul 15, 2017 at 07:09:08PM +0200, Jean-Pierre Human wrote: >> The array was setup with the below commands: >> #mdadm --create --verbose /dev/md2 --level=10 --raid-devices=4 >> /dev/sdj /dev/sdk /dev/sdl /dev/sdi > > So you didn't use a partition table? > >> root@store02:~# mdadm --examine /dev/sd[iklj] >> /dev/sdi: >> MBR Magic : aa55 >> Partition[0] : 4294967295 sectors at 1 (type ee) >> /dev/sdj: >> MBR Magic : aa55 >> Partition[0] : 4294967295 sectors at 1 (type ee) >> /dev/sdk: >> MBR Magic : aa55 >> Partition[0] : 4294967295 sectors at 1 (type ee) >> /dev/sdl: >> MBR Magic : aa55 >> Partition[0] : 4294967295 sectors at 1 (type ee) > > And then "something" created one. Is that partition table empty? > Or did it also create and format partitions, that would be worse. > > GPT partition table overwrites a bunch of sectors at both start and end. > So that's where you'll find corruption, depending which mdadm metadata > version you were using (which can also be located either start or end). > > To recover, you'll have to determine the correct RAID level / layout / > order / data offset. It's best to do this with overlays > > https://raid.wiki.kernel.org/index.php/Recovering_a_failed_software_RAID#Making_the_harddisks_read-only_using_an_overlay_file > > and only write to the real disks once you've found the setting that works. > > In the future, consider always using a partition table. Linux doesn't care * > but the partition table is the most standard way to declare a disk is > already in use and for what. Without a partition table, any software not > md-raid aware will see your drive as free, unused, and might format it. > > (*) it will happily run anything you like on bare disks > but it won't do anything to protect you, either > > Regards > Andreas Klauer Hi Andreas Thanks for the prompt response, Yes I did not use a partition table. I have always in the past used partitions but recently noticed a trend to use the device, wont do that again. I am really not sure what wrote those partitions there. I only see free space in them if I check with fdisk. I am sure it was metadata version 1.2 I will attempt to recover using the overlay, will post my results. Thanks again for your help. Regards J-P Human -- 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
