On 3/19/22 14:48, George N. White III wrote:
> On Sat, 19 Mar 2022 at 16:14, Samuel Sieb <samuel@sieb.net
> <mailto:samuel@sieb.net>> wrote:
>
>     On 3/19/22 05:18, George N. White III wrote:
>      > Or just letting btrfs create over-sized "virtual partitions" and
>     then
>      > allocating
>      > physical space as needed.
>
>     btrfs doesn't do that.  That's LVM thin-provisioning.
>
>
> Fresh install of Fedora 35 using default installation in the free space
> (after shrinking the OEM Windows partition, leaving a little over 400 GB):
>
>   % df -lhT | grep btrfs
> /dev/nvme0n1p6 btrfs     405G   89G  316G  22% /
> /dev/nvme0n1p6 btrfs     405G   89G  316G  22% /home
>   % sudo pvs -a
>    PV             VG Fmt Attr PSize PFree
>    /dev/nvme0n1p1        ---     0     0
>    /dev/nvme0n1p2        ---     0     0
>    /dev/nvme0n1p3        ---     0     0
>    /dev/nvme0n1p4        ---     0     0
>    /dev/nvme0n1p5        ---     0     0
>    /dev/nvme0n1p6        ---     0     0
>    /dev/sda1             ---     0     0
>    /dev/sda2             ---     0     0
>    /dev/sdb1             ---     0     0
>    /dev/sdb2             ---     0     0
>
> So the 405G btrfs shows / and /home sharing the 405G, and no PV's for
> lvm to use.

I don't know what you're trying to show there.  "over-size virtual
partitions" is LVM thin-provisioning.  btrfs in your case has used the
405G partition and that's all the space that's available.  It can be
used by any of the btrfs volumes, but any space that's used by one
volume is no longer available for the other ones.  Every btrfs volume
shows the same size.

If you meant something else by your initial comment, you'll need to
explain it.