I'm running debian

# uname -a
Linux thinkstation 4.9.0-6-amd64 #1 SMP Debian 4.9.88-1 (2018-04-29) x86_64 GNU/Linux

after booting today I got an error that the system wasn't able to write to /tmp because of lack of space. So I started to delete some old kernels. I'm now able to log into the system but I'm still confused about my system disk space usage:

# df -h
Filesystem      Size  Used Avail Use% Mounted on
udev            8.9G     0  8.9G   0% /dev
tmpfs           1.8G  9.4M  1.8G   1% /run
/dev/sda1        83G   78G  210M 100% /
tmpfs           8.9G  117M  8.8G   2% /dev/shm
tmpfs           5.0M  4.0K  5.0M   1% /run/lock
tmpfs           8.9G     0  8.9G   0% /sys/fs/cgroup
/dev/sda6       357G   48G  292G  14% /home
tmpfs           1.8G   20K  1.8G   1% /run/user/1000

As you can see my root partition seems to be full. Here is how I partitioned my system:

# lsblk
sda      8:0    0 465.8G  0 disk 
├─sda1   8:1    0  83.9G  0 part /
├─sda2   8:2    0     1K  0 part 
├─sda5   8:5    0  18.6G  0 part [SWAP]
└─sda6   8:6    0 363.2G  0 part /home
sr0     11:0    1  1024M  0 rom  

As you can see I've separated my home from my system (and a separate swap as well). Now if I dive into what is causing the disk usage in / I via ncdu I get the following picture:

enter image description here

As you can see the /media is taking the largest amount. However, this is a external HD where I backup my system. So why does it get counted as disk space? Is there a way to avoid this behaviour or am I really forced to delete some old backups?

1 Answer 1


You say that /media is an external HD where I backup my system. But, your df output does not list that as a separate mount point.

Perhaps you had the external drive mounted there at some point, but the simplest explanation is that you don't, now, for some reason, and so /media is just a subdirectory on /.

This theory fits well with your ncdu report, which shows ~63 GiB in /media. That plus the other parts of the tree also on the same /dev/sda1 where / is mounted add up to around the ~78 GiB shown by df.

  • it seems this is the case. looks like my external hd (old one) just dont work anymore and rsnapshot wrote directly on the disk when it couldn't find any mounted stuff there.
    – math
    May 6, 2018 at 19:53

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