Hi,

On Fri, Sep 26, 2025 at 03:49:50PM +0100, Henrik Morsing via GLLUG wrote:
> Block devices, filesystems, mkfs tools, udev and the Debian installer
> should all follow an agreed design.

These are all different projects from different orgs. What you ask for
would be a radical departure from how free software has traditionally
organically grown and is more akin to centralised efforts like the BSDs
- which you presumably do not use for a reason.

There are trade-offs in everything.

Another view is that if things should always follow "agreed design"
there'd be no Linux because MINIX is good enough and microkernels are
the future anyway. There'd be no ZFS because volume management and fault
tolerance in the filesystem is a layering violation, and on and on.

> However, mkfs should warn and when I choose "complete disk with
> auto-partitioning" in the Debian installer, it should start by wiping
> these signatures.

I think there is a good argument for a wishlist bug in debian-installer
to detect signatures and offer to wipe them before using a thing for
something else.

I bet there are quite a few other Linux distro installers that wouldn't
have spotted the ZFS signatures either.

> I can still not quite get my head around how this signature ended up
> on a device that the Debian installer created though.

In the bug report you said you had used the device for ZFS in the past.

Partitioning disks and creating filesystems on those partitions doesn't
erase the entire content of the disk. Remnants of things from before
will remain, like different kinds of disk label (GPT, MBR, other OS
labels…), LVM and MD metadata, and so on. These different technologies
all have different ideas about how to do things and where on disks to
keep their private data. Just saying, "everyone should really agree on
how to do this" is easy… and in danger of the XKCD "one more standard"
fate.

But like I say, existing software clearly finds these signatures, wipefs
clearly knows what to do (with guidance), so it seems reasonable to
suggest some usability improvements.

Note also that as ZFS is developed outside of the Linux ecosystem it's
always going to be more difficult to co-ordinate, even by the low
standards of current co-ordination.

Thanks,
Andy

PS Did you know that there are motherboards on sale today that will
   REGENERATE A GPT LABEL on a disk at boot time if they spot a backup
   GPT signature at the end of the disk and no such thing at the start?
   The board firmware assumes the disk to have become corrupted and
   helpfully fixes it without being asked. People have lost their RAIDs
   over this, by using entire disk as RAID member and not cleaning the
   backup GPT first with wipefs.

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