VPS Backup disk - unmounting

Stupid question time. I have a VPS server with 7 days worth of backups. I have mounted a backup disk via the dashboard OK (this makes it available to my VPS). I can see this disk as sdb1 via **lsblk** and can mount it OK (see below, output from lsblk)

sda 8:0 0 160G 0 disk
sda1 8:1 0 159.9G 0 part /
sda14 8:14 0 4M 0 part
sda15 8:15 0 106M 0 part /boot/efi
sdb 8:16 0 160G 0 disk
**sdb1 8:17 0 159.9G 0 part**
sdb14 8:30 0 4M 0 part

I've mounted it on the server and recovered my data OK. So no problem there. However, there is no option on the ovh dashboard to 'unmount' the backup disk so what happens if I want to mount another of my 7 backups? Will a new disk take the place of sdb or will it create a sdc and so on? If so, how do I prevent unauthorized access to the backup disk? In other words how do I make the backup disks disappear from **lsblk**

NOTE: I'm not talking about unmounting it from the OS (I've already done that : **unmount /mnt/restore** ). I just want it to disappear from lsblk when I'm not using it.