Ubuntu Server 16.04 filesystem usage

Question

I have installed ubuntu server 16.04 as a webserver at work. I had initially allocated 100GB to it. For some reason, some of the space has been eaten up by tmpfs and I am not able to claim it back.

Here is what i get when I run df -h

Filesystem                           Size  Used Avail Use% Mounted on
udev                                  31G     0   31G   0% /dev
tmpfs                                6.2G  8.9M  6.2G   1% /run
/dev/mapper/filesystem--vg-root       36G   34G  238M 100% /
tmpfs                                 31G     0   31G   0% /dev/shm
tmpfs                                5.0M     0  5.0M   0% /run/lock
tmpfs                                 31G     0   31G   0% /sys/fs/cgroup
/dev/sda1                            472M   57M  391M  13% /boot
tmpfs                                6.2G     0  6.2G   0% /run/user/1000

It appears that my / folder is full. Which is not supposed to be the case. The server has already used up the 36GB only. Please help someone.

Answer 1

As understand from the comments OP have very huge swap partition. Here is the procedure to shrink it to the reasonable size:

1. Disable swap: swapoff /dev/mapper/thitoacademics--vg-swap_1
2. Change the swap LV to 4GB: lvreduce -L 4G /dev/mapper/thitoacademics--vg-swap_1
3. Recreate new swap (just in case): mkswap /dev/mapper/thitoacademics--vg-swap_1
4. Add new swap: swapon /dev/mapper/thitoacademics--vg-swap_1

All those commands need to be executed as root

For moving the free diskspace to the other LV/filesystem you should follow those steps:

1. Extend the other filesystem:

lvextend -L+4G /dev/mapper/filesystem--vg-root

2. Extend the filesystem

resize2fs /dev/mapper/filesystem--vg-root

Again all those commands need to be executed as root