need help mounting my LVM volume

I set up a LVM volume on an external hard drive. I mounted this drive to another machine. Here is what it looks like:

Code: --- Physical volume ---
PV Name /dev/sda1
VG Name vg-main
PV Size 931.48 GiB / not usable 3.98 MiB
Allocatable yes
PE Size 4.00 MiB
Total PE 238458
Free PE 235898
Allocated PE 2560
PV UUID 87oFY6-8MaZ-pQ98-ncMV-Swh3-nOBm-om3MTf

--- Physical Segments ---
Physical extent 0 to 2559:
Logical volume /dev/vg-main/data
Logical extents 0 to 2559
Physical extent 2560 to 238457:
FREECode:lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
loop0 7:0 0 45.5M 1 loop /snap/core18/1706
loop1 7:1 0 22.4M 1 loop /snap/snapd/7266
loop2 7:2 0 45.5M 1 loop /snap/core18/1751
loop3 7:3 0 54.2M 1 loop /snap/lxd/14807
loop4 7:4 0 54.3M 1 loop /snap/lxd/15362
loop5 7:5 0 25M 1 loop /snap/snapd/7779
sda 8:0 0 931.5G 0 disk
sda1 8:1 0 931.5G 0 part
vg--main-data 253:0 0 10G 0 lvm
mmcblk0 179:0 0 14.5G 0 disk
mmcblk0p1 179:1 0 256M 0 part /boot/firmware
mmcblk0p2 179:2 0 14.3G 0 part /it is currently not mounted:

Code:df -h /opt
Filesystem Size Used Avail Use% Mounted on
/dev/mmcblk0p2 14G 2.2G 12G 16% /I would normally mount it like this:

Code:sudo mount /dev/vg-main/data /optthe command executes silently. The results are unimpressive:

Code:df -h /opt
Filesystem Size Used Avail Use% Mounted on
/dev/mmcblk0p2 14G 2.2G 12G 16% /I cannot mount the device directly:

Code:sudo mount /dev/sda1 /opt
mount: /opt: unknown filesystem type 'LVM2_member'.which makes sense, because there's no filesystem on sda1.

somehow I don't see what I did wrong, I am not using LVMs a lot so I am probably missing something stupid :redface: