restoring stream+compressed backup to original allocation, not thin-provisioned?

[pgnd]

i've installed a source rpm build of v2.13 branch

distro
	Name: Fedora Linux 40 (Forty)
	Version: 40
	Codename:

rpm -qa virtnbdbackup
	virtnbdbackup-git_v2.13-0.20240824_210126.fc40.x86_64

virtnbdbackup -V
	2.13

i've a vm up & running

virsh list --all
	 Id   Name   State
	----------------------
	 4    test     running

it's preallocated to ~50G

ls -al /kvms/test.qcow2
	-rw------- 1 qemu qemu 51G Aug 24 18:52 /kvms/test.qcow2

but actual usage in guest is, atm, ~5G

du --summarize /
	4.9G    /

live backup via stream + compress works, thin provisioning via stream as expected,

virtnbdbackup \
 --domain test \
 --level full \
 --scratchdir /tmp \
 --compress \
 --output - \
> /BKUP/test.bkup.zip

ls -al /BKUP/test.bkup.zip
	-rw-r--r-- 1 root root 2.5G Aug 24 18:00 /BKUP/test.bkup.zip

subsequent restore

virsh shutdown test
mv /kvms/test.qcow2 /kvms/test.qcow2.OLD

unzip ./test.bkup.zip -d /tmp/extract

virtnbdrestore \
 --input /tmp/extract \
 --output /kvms/

virsh start test

works; guest's up & operational.

but, the qcow2's restored to nominal size,

ls -al /kvms/
	-rw-r--r-- 1 root root 5.8G Aug 24 18:18 /kvms/test.qcow2

not its originally allocated ~50G.

i can certainly reallocate and resize with qemu-img, etc afterwards, and restore to exact original guest config,

df -h
	Filesystem                Type      Size  Used Avail Use% Mounted on
	/dev/mapper/VG0-ROOT      ext4       47G  4.3G   40G  10% /
	devtmpfs                  devtmpfs  4.0M     0  4.0M   0% /dev
	tmpfs                     tmpfs     3.8G  2.5M  3.8G   1% /dev/shm
	efivarfs                  efivarfs  256K   54K  198K  22% /sys/firmware/efi/efivars
	tmpfs                     tmpfs     1.6G  852K  1.6G   1% /run
	tmpfs                     tmpfs     3.8G     0  3.8G   0% /tmp
	tmpfs                     tmpfs      16M  4.0K   16M   1% /var/log/valkey
	/dev/vda2                 ext4      1.9G  323M  1.5G  19% /boot
	/dev/vda1                 vfat      572M  7.5M  564M   2% /boot/efi

but that can get a bit messy/tedious.

is there a 'built-in' virtnbdbackup + virtnbdrestore procedure that gets me the maximum size reduction of the backup -- as above with stream + compress --

AND

restores to the original disk/filesystem allocation(s)?

[abbbi]

hi again,

i think your desired behavior would be if the restore creates the image with preallocate=full option, this works by now using
the --preallocate option in virtnbdrestore.