Ubuntu not mounting entire drive (anymore)

I can not update my ubuntu-server anymore.df says / has still only 4.7M, but lsblk says 74GB...Also to me, it looks like 74GB from /dev/sda3 are not mounted at all.So far these settings are all default, no changes in `/etc/fstab'.Before my reboot, this was mounted. Do I now have to manually mount it?Where should I mount it to?

Thank you,

nessie@media:~$ sudo apt-get updateHit:1 http://ch.archive.ubuntu.com/ubuntu focal InReleaseGet:2 http://ch.archive.ubuntu.com/ubuntu focal-updates InRelease [111 kB]Err:2 http://ch.archive.ubuntu.com/ubuntu focal-updates InRelease  Error writing to output file - write (28: No space left on device) [IP: 2001:1620::1620 80]Get:3 http://ch.archive.ubuntu.com/ubuntu focal-backports InRelease [98.3 kB]Err:3 http://ch.archive.ubuntu.com/ubuntu focal-backports InRelease  Error writing to output file - write (28: No space left on device) [IP: 2001:1620::1620 80]Get:4 http://ch.archive.ubuntu.com/ubuntu focal-security InRelease [107 kB]Err:4 http://ch.archive.ubuntu.com/ubuntu focal-security InRelease  Error writing to output file - write (28: No space left on device) [IP: 2001:1620::1620 80]Get:5 https://download.docker.com/linux/ubuntu focal InRelease [36.2 kB]Err:5 https://download.docker.com/linux/ubuntu focal InRelease  Error writing to output file - write (28: No space left on device) [IP: 2600:9000:2190:ee00:3:db06:4200:93a1 443]Reading package lists... DoneW: Failed to fetch http://ch.archive.ubuntu.com/ubuntu/dists/focal-updates/InRelease  Error writing to output file - write (28: No space left on device) [IP: 2001:1620::1620 80]W: Failed to fetch http://ch.archive.ubuntu.com/ubuntu/dists/focal-backports/InRelease  Error writing to output file - write (28: No space left on device) [IP: 2001:1620::1620 80]W: Failed to fetch http://ch.archive.ubuntu.com/ubuntu/dists/focal-security/InRelease  Error writing to output file - write (28: No space left on device) [IP: 2001:1620::1620 80]W: Failed to fetch https://download.docker.com/linux/ubuntu/dists/focal/InRelease  Error writing to output file - write (28: No space left on device) [IP: 2600:9000:2190:ee00:3:db06:4200:93a1 443]W: Some index files failed to download. They have been ignored, or old ones used instead.

nessie@media:~$ df -ihFilesystem                        Inodes IUsed IFree IUse% Mounted onudev                                238K   601  237K    1% /devtmpfs                               249K   981  248K    1% /run/dev/mapper/ubuntu--vg-ubuntu--lv   4.7M  300K  4.4M    7% /tmpfs                               249K     4  249K    1% /dev/shmtmpfs                               249K     3  249K    1% /run/locktmpfs                               249K    18  249K    1% /sys/fs/cgroup/dev/sda2                            64K   312   64K    1% /boot/dev/loop0                           13K   13K     0  100% /snap/core/9993/dev/loop1                           13K   13K     0  100% /snap/core/10126/dev/loop2                           11K   11K     0  100% /snap/core18/1885/dev/loop3                          3.4K  3.4K     0  100% /snap/docker/471/dev/loop4                           11K   11K     0  100% /snap/core18/1880/dev/loop5                          1.5K  1.5K     0  100% /snap/lxd/16099/dev/loop7                           472   472     0  100% /snap/snapd/9279/dev/loop6                          1.5K  1.5K     0  100% /snap/lxd/16922/dev/loop8                           472   472     0  100% /snap/snapd/9607tmpfs                               249K    22  249K    1% /run/user/1000tmpfs                               249K     1  249K    1% /tmp

nessie@media:~$ sudo lsblk -o NAME,FSTYPE,SIZE,MOUNTPOINT,LABELNAME                      FSTYPE        SIZE MOUNTPOINT        LABELfd0                                       4Kloop0                     squashfs     97.1M /snap/core/9993loop1                     squashfs     97.7M /snap/core/10126loop2                     squashfs     55.3M /snap/core18/1885loop3                     squashfs    125.9M /snap/docker/471loop4                     squashfs       55M /snap/core18/1880loop5                     squashfs     71.3M /snap/lxd/16099loop6                     squashfs     70.6M /snap/lxd/16922loop7                     squashfs     30.3M /snap/snapd/9279loop8                     squashfs       31M /snap/snapd/9607sda                                   149.1G├─sda1                                    1M├─sda2                    ext4            1G /boot└─sda3                    LVM2_member   148G└─ubuntu--vg-ubuntu--lv ext4           74G /

nessie@media:~$ sudo fdisk -lDisk /dev/sda: 149.5 GiB, 160041885696 bytes, 312581808 sectorsDisk model: SAMSUNG SP1654NUnits: sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 512 bytesI/O size (minimum/optimal): 512 bytes / 512 bytesDisklabel type: gptDisk identifier: 8DDAC3C1-57E4-48A1-A034-8A905F32B3EDDevice       Start       End   Sectors  Size Type/dev/sda1     2048      4095      2048    1M BIOS boot/dev/sda2     4096   2101247   2097152    1G Linux filesystem/dev/sda3  2101248 312578047 310476800  148G Linux filesystem

nessie@media:~$ cat /etc/fstab# /etc/fstab: static file system information.## Use 'blkid' to print the universally unique identifier for a# device; this may be used with UUID= as a more robust way to name devices# that works even if disks are added and removed. See fstab(5).## <file system> <mount point>   <type>  <options>       <dump>  <pass># / was on /dev/ubuntu-vg/ubuntu-lv during curtin installation/dev/disk/by-id/dm-uuid-LVM-y3gRYv9ja3ZkF0FDdztxzsx3gEldTa9qd9BJmfvrTVf5tkOfaTFTu60KPYX6oueM / ext4 defaults 0 0# /boot was on /dev/sda2 during curtin installation/dev/disk/by-uuid/b1593203-e59b-4cd0-af2b-4bf7b273e1d3 /boot ext4 defaults 0 0/swap.img   none    swap    sw  0   0

nessie@media:~$ blkid/dev/sda2: UUID="b1593203-e59b-4cd0-af2b-4bf7b273e1d3" TYPE="ext4" PARTUUID="36cb0c83-ec38-4971-bc17-2f3554b41d47"/dev/sda3: UUID="aO2T4S-ZxEU-RyLI-U7nG-gPYY-dGiL-AnyB1t" TYPE="LVM2_member" PARTUUID="09fba423-bee5-4104-b9e3-015d3528b8f9"/dev/mapper/ubuntu--vg-ubuntu--lv: UUID="e3de6996-c10d-473c-9882-12ba559b7d6b" TYPE="ext4"