E: Write error - write (28: No space left on device)

Question

Is it possible to solve the space problem below as root user? Any idea which disk/folder is full, causing installation of new software impossible?

root@fba-bod-p1:/mnt/# apt install setuptools-scm
Reading package lists... Error!
E: Write error - write (28: No space left on device)
E: IO Error saving source cache
E: The package lists or status file could not be parsed or opened.
root@fba-bod-p1:/mnt/# df -i
Filesystem                                Inodes   IUsed     IFree IUse% Mounted on
tmpfs                                   16483401    1476  16481925    1% /run
/dev/mapper/ubuntu--vg-ubuntu--lv        6553600  356895   6196705    6% /
tmpfs                                   16483401       1  16483400    1% /dev/shm
tmpfs                                   16483401       4  16483397    1% /run/lock
1:2                                     63753378 2731153  61022225    5% /mnt/backup
/dev/sda2                                 131072     313    130759    1% /boot
/dev/sda1                                      0       0         0     - /boot/efi
158.39.32.194:/vol/vol_13122022_101029  31876689      96  31876593    1% /mnt/netapp1
158.39.32.196:/vol/vol_13122022_100726  31876689 2731057  29145632    9% /mnt/netapp2
tmpfs                                    3296680     143   3296537    1% /run/user/1000
/dev/sdc1                              610469888   18352 610451536    1% /mnt/encl_vol2
/dev/sdb1                              610469888 2227070 608242818    1% /home/fatima
tmpfs                                    3296680      74   3296606    1% /run/user/1001
tmpfs                                    3296680      68   3296612    1% /run/user/1004
tmpfs                                    3296680      76   3296604    1% /run/user/1027

df

Filesystem                              Size  Used Avail Use% Mounted on
tmpfs                                    13G  1.3G   12G  11% /run
/dev/mapper/ubuntu--vg-ubuntu--lv        98G   98G     0 100% /
tmpfs                                    63G     0   63G   0% /dev/shm
tmpfs                                   5.0M     0  5.0M   0% /run/lock
1:2                                      37T   20T   18T  54% /mnt/backup
/dev/sda2                               2.0G  260M  1.6G  15% /boot
/dev/sda1                               1.1G  5.3M  1.1G   1% /boot/efi
158.39.32.194:/vol/vol_13122022_101029   17T  5.5G   17T   1% /mnt/netapp1
158.39.32.196:/vol/vol_13122022_100726   20T   20T  117G 100% /mnt/netapp2
tmpfs                                    13G  116K   13G   1% /run/user/1000
/dev/sdc1                                37T  8.3T   27T  24% /mnt/encl_vol2
/dev/sdb1                                37T   30T  5.4T  85% /home/fatima
tmpfs                                    13G   64K   13G   1% /run/user/1001
tmpfs                                    13G   64K   13G   1% /run/user/1004
tmpfs                                    13G   68K   13G   1% /run/user/1027

Answer 1

It’s this one:

/dev/mapper/ubuntu--vg-ubuntu--lv        98G   98G     0 100% /

Finding largest file recursively will help you find the largest files, which may include candidates for removal.

If ncdu is already installed, you might find it useful to identify large directories:

ncdu -x /

You might find Which installed software packages use the most disk space on Debian? useful too, although the answers there will probably involve installing additional software which will be difficult in your case.