I'm stuck ...
root@X230:/qubes# ls -la /dev/mapper/
total 0
drwxr-xr-x 2 root root 80 Dec 8 17:50 .
drwxr-xr-x 21 root root 4460 Dec 8 17:50 ..
crw------- 1 root root 10, 236 Dec 8 17:26 control
lrwxrwxrwx 1 root root 7 Dec 8 17:50 qubes -> ../dm-0
root@X230:/qubes# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 119,2G 0 disk
└─sda1 8:1 0 119,2G 0 part /
sdb 8:16 0 931,5G 0 disk
└─sdb1 8:17 0 930,6G 0 part /media/user/1tb-ext4
sdc 8:32 0 465,8G 0 disk
├─sdc1 8:33 0 1G 0 part
└─sdc2 8:34 0 464,8G 0 part
└─qubes 253:0 0 464,8G 0 crypt
root@X230:/qubes# mount /dev/mapper/qubes /qubes
mount: /qubes: unknown filesystem type 'LVM2_member'.
root@X230:/qubes# lvmdiskscan
Incorrect metadata area header checksum on /dev/mapper/qubes at offset 4096
/dev/mapper/qubes [ <464,76 GiB] LVM physical volume
/dev/sda1 [ 119,24 GiB]
/dev/sdb1 [ 930,61 GiB]
/dev/sdc1 [ 1,00 GiB]
/dev/sdc2 [ 464,76 GiB]
0 disks
4 partitions
1 LVM physical volume whole disk
0 LVM physical volumes