It's really my first time to start a thread and I'm not an expert on Linux.
This problem may look simple to you. But I had an experience removing all of my data in the hard disks doing on my own.
I have two hard disks(2TB * 2).
One of them(sdb1) works fine. It's used for backup.
I found that I was using up /dev/mapper/fedora-root which is small, not /fedora-home.
I don't know why It's already been used up 99%.
Please explain like I'm 5. Thanks in advance! Btw, I'm using fedora 19.
[root@localhost ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/fedora-root 50G 27G 21G 57% /
devtmpfs 32G 0 32G 0% /dev
tmpfs 32G 824K 32G 1% /dev/shm
tmpfs 32G 1.4M 32G 1% /run
tmpfs 32G 0 32G 0% /sys/fs/cgroup
tmpfs 32G 196K 32G 1% /tmp
/dev/sda1 477M 119M 330M 27% /boot
/dev/mapper/fedora-home 1.8T 1.6T 29G 99% /home
/dev/sdb1 1.8T 757G 984G 44% /run/media/novice/backup