ok, so to sum it up :
i added a new empty drive in the slot 23 of my NAS
so i have in slots 0 to 11, 12 disks, making one RAID6 unit where there is my VG0)
now, i will reboot my NAS, open the web interface, and try to create a new VG on that disk in the slot23. Let's say VG1.
then i can create a new share, on this VG1.
how to backup the data from my VG0 to my VG1 ?

i could renew my support licence, but im closer to buy a new equipement, cause this one is getting a bit old. So i'd like to get my datas back and start to choose my future solution