Re: How to make btrfs forget a disk?

From	Victor Sudakov <vas@sibptus.ru>
Newsgroups	linux.debian.user
Subject	Re: How to make btrfs forget a disk?
Date	2021-03-12 11:00 +0100
Message-ID	<BRMKn-6SQ-11@gated-at.bofh.it> (permalink)
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David wrote:
> On Fri, 12 Mar 2021 at 20:17, Victor Sudakov <vas@sibptus.ru> wrote:
> > deloptes wrote:
> 
> > > > "wipefs -t btrfs -f -a /dev/nvme1n1" did the job.
> 
> > > > Still wondering where those labels are stored on disk in Linux.
> 
> > > FS Superblock?
> 
> > Well, the FS (btrfs in this case) was not there already, but the magic
> > label was still there somewhere.
> 
> My new knowledge after 5 seconds of searching, ...
> 
> https://en.wikipedia.org/wiki/Btrfs#Superblock
> says that there are multiple copies of the superblock.

Many filesystems have multiple copies of the superblock (e.g. UFS and ext*).

What surprised and worried me is the fact that they persisted after the
disk was converted to ZFS, and btrfs continued to recognize this
filesystem as its own (albeit unmounted).

> 
> And the on-disk format is here:
>   https://btrfs.wiki.kernel.org/index.php/On-disk_Format

> 
> And maybe if the drive was once part of a multiple
> device filesystem it might be referenced in superblocks
> on other devices.
> 

No, it was not.

-- 
Victor Sudakov VAS4-RIPE
http://vas.tomsk.ru/
2:5005/49@fidonet

Thread

How to make btrfs forget a disk? Victor Sudakov <vas@sibptus.ru> - 2021-03-12 03:40 +0100
  Re: How to make btrfs forget a disk? David <bouncingcats@gmail.com> - 2021-03-12 04:20 +0100
    Re: How to make btrfs forget a disk? Victor Sudakov <vas@sibptus.ru> - 2021-03-12 04:50 +0100
      Re: How to make btrfs forget a disk? Victor Sudakov <vas@sibptus.ru> - 2021-03-12 06:20 +0100
        Re: How to make btrfs forget a disk? deloptes <deloptes@gmail.com> - 2021-03-12 08:00 +0100
          Re: How to make btrfs forget a disk? Victor Sudakov <vas@sibptus.ru> - 2021-03-12 10:20 +0100
            Re: How to make btrfs forget a disk? David <bouncingcats@gmail.com> - 2021-03-12 10:40 +0100
              Re: How to make btrfs forget a disk? Victor Sudakov <vas@sibptus.ru> - 2021-03-12 11:00 +0100
            Re: How to make btrfs forget a disk? deloptes <deloptes@gmail.com> - 2021-03-12 12:10 +0100
        Re: How to make btrfs forget a disk? Anssi Saari <as@sci.fi> - 2021-03-12 09:20 +0100
          Re: How to make btrfs forget a disk? Victor Sudakov <vas@sibptus.ru> - 2021-03-12 10:30 +0100
      Re: How to make btrfs forget a disk? David <bouncingcats@gmail.com> - 2021-03-12 10:30 +0100
        Re: How to make btrfs forget a disk? Victor Sudakov <vas@sibptus.ru> - 2021-03-12 11:10 +0100
  Re: How to make btrfs forget a disk? Andrei POPESCU <andreimpopescu@gmail.com> - 2021-03-12 17:10 +0100
    Re: How to make btrfs forget a disk? Victor Sudakov <vas@sibptus.ru> - 2021-03-14 05:00 +0100
      Re: How to make btrfs forget a disk? Andrei POPESCU <andreimpopescu@gmail.com> - 2021-03-14 10:50 +0100
        Re: How to make btrfs forget a disk? Victor Sudakov <vas@sibptus.ru> - 2021-03-14 11:40 +0100
          Re: How to make btrfs forget a disk? Andrei POPESCU <andreimpopescu@gmail.com> - 2021-03-14 12:20 +0100
            Re: How to make btrfs forget a disk? Victor Sudakov <vas@sibptus.ru> - 2021-03-15 04:50 +0100
  Re: How to make btrfs forget a disk? Victor Sudakov <vas@sibptus.ru> - 2021-03-16 03:20 +0100

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