Re: What is the proper way to remove an xfs partition?

Eric Sandeen
2017-08-31T18:16:17Z

xOn 8/31/17 1:04 PM, ToddAndMargo wrote:
> Hi All,
>
> Fedora 26
> BIOS boot = legacy (EUFI give me hives)
>
> I have a SATA backup drive formatted gpt, one partition, xfs. I went into gparted, erased the partition, recreated the partition as ext4 and formatted it as ext4.
>
> Then I mounted it as ext4, copied some files to it, unmounted it. When I went to remount it, mount told me there was something wrong with ext4.

What "something" was that?

> So I mounted it as xfs AND IT WORKED! I repeated with the same result. The drive thinks it is ext4 until the second mount.

This should not be the case. It's possible to leave old magic numbers & signatures lying around in general, but mkfs.ext4, in my testing, zeros out the XFS superblock at offset 0; xfs should fail to mount after that. It sounds like there may be more going on, here.

> Out of shear frustration, I did a dd /dev/zero overwrite of the stinker and left it running overnight.  That did the trick, but it takes
> forever and I have four more drives to go.
>
> What is the official way to remove an xfs partition?

It's not usually needed, but if you don't want the kernel and/or utilities to recognize an xfs block device as xfs anymore, simply zero the first 512 bytes of that block device.

Or more conveniently, there's also the wipefs utility:

NAME
wipefs - wipe a signature from a device

-Eric