I use the minimal Photon distribution and it seems the system disk is only around 8GB.

That fills up quickly when installing some humongous Docker containers :/

List usage

df -h

Check available space on disk

fdisk -l

Install Diskpart

tdnf install parted

Diskpart

parted
print free

Increase size

resizepart
2
100000

print free
quit

Reboot

reboot

Resize filesystem

resize2fs /dev/sda2

df -h

And a reboot just for good measure