Yesterday I was installing btrfs when I gave the fatal command to format a partition but forgot the partition number! So the drive was wiped and the functioning RAID devices (a RAID1 and a RAID5) were decommissioned. I used sgdisk to duplicate the partition structure from a mated disk and got everything working again.
I went to install grub2 from a chroot into the newly formatted and set up disk and received the following unpleasant news:
Quote:
(chroot) anuday linux # grub2-install /dev/sde
Installing for i386-pc platform.
grub2-install: warning: Attempting to install GRUB to a disk with multiple partition labels. This is not supported yet..
grub2-install: error: filesystem `btrfs' doesn't support blocklists.
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This was odd, because I installed grub2 before I wiped the disk when it was similarly set up. I consulted the great guru Google, and found that someone else had the same experience after reformatting a btrfs drive and found that there were crumbs left over from the previous formatting. He got rid of those and voila! Grub installed.
So I checked for my own crumbs. A standard command yielded the following:
Quote:
(chroot) anuday linux # btrfs filesystem show
Label: none uuid: 500fceed-d724-4661-bcab-0e666b1ed414
Total devices 2 FS bytes used 6.89GiB
devid 1 size 20.42GiB used 8.03GiB path /dev/sdb2
devid 2 size 20.42GiB used 8.03GiB path /dev/sde2
Label: none uuid: b1d9ba96-64b5-45e6-87a2-56f51c8a68dd
Total devices 4 FS bytes used 130.75GiB
devid 1 size 232.89GiB used 44.38GiB path /dev/sda
devid 2 size 232.89GiB used 44.38GiB path /dev/sdc
devid 3 size 232.89GiB used 44.38GiB path /dev/sdb1
devid 4 size 232.89GiB used 44.38GiB path /dev/sde1
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All good, and as it should be. But then I used the command used by the person in the forum I consulted and got the following:
Quote:
(chroot) anuday linux # btrfs fi show --all
Label: none uuid: df3b59ab-a1ac-4b9c-b551-e17fbab435b7
Total devices 1 FS bytes used 112.00KiB
devid 1 size 1.82TiB used 2.04GiB path /dev/sde
Label: none uuid: b1d9ba96-64b5-45e6-87a2-56f51c8a68dd
Total devices 4 FS bytes used 130.75GiB
devid 1 size 232.89GiB used 44.38GiB path /dev/sda
devid 2 size 232.89GiB used 44.38GiB path /dev/sdc
devid 3 size 232.89GiB used 44.38GiB path /dev/sdb1
devid 4 size 232.89GiB used 44.38GiB path /dev/sde1
Label: none uuid: 500fceed-d724-4661-bcab-0e666b1ed414
Total devices 2 FS bytes used 6.89GiB
devid 1 size 20.42GiB used 8.03GiB path /dev/sdb2
devid 2 size 20.42GiB used 8.03GiB path /dev/sde2
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Omigod! It listed not only the expected btrfs arrays but also the UUID that resulted from the accidental reformatting of the entire drive! This, I am guessing, is the culprit crumb.
Does anyone know how to zap this tragic reminder of yesterday's errant keystroke (or lack thereof)? Can I erase this UUID without having to once more reformat the drive and copy all the files? Any help is greatly appreciated.