Re: How to make btrfs forget a disk?

[Anssi Saari <as@sci.fi>]

Victor Sudakov <vas@sibptus.ru> writes:

> "wipefs -t btrfs -f -a /dev/nvme1n1" did the job.
>
> Still wondering where those labels are stored on disk in Linux.

Didn't wipefs tell you? I don't have any btrfs but for me wipefs prints
at which offset it found which label. Like this, for a Linux swap
partition:

# wipefs /dev/sdb5
DEVICE OFFSET TYPE UUID                                 LABEL
sdb5   0xff6  swap 8af9fb67-38ca-4c91-bbbd-d53c5ac1f30a 

And if I hexdump a bit of /dev/sdb5 I get:

000ff0 00 00 00 00 00 00 53 57 41 50 53 50 41 43 45 32  >......SWAPSPACE2<
001000 01 00 00 00 8a f9 fb 67 38 ca 4c 91 bb bd d5 3c  >.....ùûg8ÊL.»½Õ<<
001010 5a c1 f3 0a 00 00 15 00 80 00 ff ff ff ff 03 00  >ZÁó.......ÿÿÿÿ..<
001020 00 00 01 00 00 00 00 00 00 00 3d b5 04 00 00 00  >..........=µ....<