@Impact
lvcreate -l +95%FREE -T -n data vmdata
.. went fine, but
root@pve:~# pvesm add lvmthin --vgname vmdata --thinpool data local-lvm
create storage failed: storage ID 'local-lvm' already defined
Trying to add a secondary hdd to my new proxmox-9 installation I managed to loose the data lv.
root@pve:~# lvs
LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert
root pve -wi-ao---- 12.66g...