Chasing down a bug report https://bugs.launchpad.net/ubuntu/+source/ubiquity/+bug/1828558 where installing over a device previously used in a RAID array, I found that parted's mklabel does not erase mdraid metadata 0.90 metadata (and only that version). Here's my test script
#!/bin/bash set -xeu parted --version rm -f image.img truncate -s 1G image.img n=$(uuidgen | cut -d- -f1) dev="$(losetup -Pf --show image.img)" mdadm --create --metadata 0.90 --force --level 1 -n 1 --assume-clean /dev/md/$n $dev mdadm --stop /dev/md/$n losetup -d $dev parted --script --align optimal image.img -- mklabel msdos wipefs image.img and here's the output on my system: + parted --version parted (GNU parted) 3.2 Copyright (C) 2014 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html >. This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Written by < http://git.debian.org/?p=parted/parted.git;a=blob_plain;f=AUTHORS>. + rm -f image.img + truncate -s 1G image.img ++ uuidgen ++ cut -d- -f1 + n=e0c43267 ++ losetup -Pf --show image.img + dev=/dev/loop44 + mdadm --create --metadata 0.90 --force --level 1 -n 1 --assume-clean /dev/md/e0c43267 /dev/loop44 mdadm: array /dev/md/e0c43267 started. + mdadm --stop /dev/md/e0c43267 mdadm: stopped /dev/md/e0c43267 + losetup -d /dev/loop44 + parted --script --align optimal image.img -- mklabel msdos + wipefs image.img DEVICE OFFSET TYPE UUID LABEL image.img 0x3fff0000 linux_raid_member 6dbbfe69-809c-7a77-14d5-894fb9296617 image.img 0x1fe dos Looking at ped_disk_clobber none of this is surprising: the 0.90 metadata is somewhere between 127 and 64 kiB from the end of the device and this isn't touched. If this is indeed deemed a bug it could be pragmatically fixed by wiping more from the end of the disk or more cleverly by using libblkid to locate and zap all superblocks. Cheers, mwh
