Root / is full

[rdonnelly]

For years I always gave / 20 GB of space, and it always has worked out well, and never got more than half full. Then I started having problems where programs were complaining that /tmp was full, so I rebooted and got "xsession warning unable to write to /tmp". Luckily I had a backup of my / and that is how I solved it. But I still only had 300 MB of space. So I deleted all the Apt files, and cleared out the /tmp folder. Now I have 2 GB of space left.

How come Kubuntu is not keeping / cleaned up?

Thanks

[Fred47]

I'm assuming you have separate root and home partitions. If you combine them onto one this problem will go away. My root is currently at 16.9 GB I'm not aware of any distro that does the maintenance for you, but I could be missing something.

[jglen490]

If there is a space problem in /, then combining / and /home will not solve the problem. Doing that will eventually allow both to overflow.

My / directory is on its own partition that is sized at 28 GB, with about 9.1 GB in files. This goes up and down, based on activity, installing apps, installing updates, and the like. In general, / fills up very slowly.

One of the best things you can do is to periodically run:

sudo apt autoremove

sudo apt autoclean

sudo apt clean

I do this after every update/upgrade, and it removes temporary files no longer needed. These quite often remove a couple hundred MB of junk.

I just now did it, and about 100 MB was cleared out.

df -h
Filesystem      Size  Used Avail Use% Mounted on
udev            5.7G     0  5.7G   0% /dev
tmpfs           1.2G  2.1M  1.2G   1% /run
/dev/nvme0n1p2   28G  9.1G   17G  35% /
tmpfs           5.8G  940K  5.8G   1% /dev/shm
tmpfs           5.0M  4.0K  5.0M   1% /run/lock
tmpfs           5.8G     0  5.8G   0% /sys/fs/cgroup
/dev/nvme0n1p1   93M  7.9M   85M   9% /boot/efi
/dev/nvme0n1p3  426G  274G  131G  68% /home
tmpfs           1.2G   16K  1.2G   1% /run/user/1000
[john@john-HP-ENVY-x360 ~]$ sudo apt autoremove
[sudo] password for john: 
Reading package lists... Done
Building dependency tree       
Reading state information... Done
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
[john@john-HP-ENVY-x360 ~]$ sudo apt autoclean
Reading package lists... Done
Building dependency tree       
Reading state information... Done
[john@john-HP-ENVY-x360 ~]$ sudo apt clean
[john@john-HP-ENVY-x360 ~]$ df -h
Filesystem      Size  Used Avail Use% Mounted on
udev            5.7G     0  5.7G   0% /dev
tmpfs           1.2G  2.1M  1.2G   1% /run
/dev/nvme0n1p2   28G  9.0G   17G  35% /
tmpfs           5.8G  940K  5.8G   1% /dev/shm
tmpfs           5.0M  4.0K  5.0M   1% /run/lock
tmpfs           5.8G     0  5.8G   0% /sys/fs/cgroup
/dev/nvme0n1p1   93M  7.9M   85M   9% /boot/efi
/dev/nvme0n1p3  426G  274G  131G  68% /home
tmpfs           1.2G   16K  1.2G   1% /run/user/1000

[jlittle]

I suggest having a look in /var/log. I've found GB of old logs in there sometimes.

I have to run sudo journalctl --vacuum-size=100M periodically (on an Ubuntu instance I have on Linode, partly because it is internet-facing and gets a huge amount of connection attempts sometimes, even with fail2ban).

I would check /boot to make sure there's two kernels (vimlinuz*, initrd.img*, and System.map*). Sometimes I've had kernels get left behind by a release upgrade. The space taken up by such a kernel is mostly not in /boot but /usr; if you have got an old kernel that shouldn't be there use apt (or your favourite apt tool, mine's muon) to remove it.

[jlittle]

I'm assuming you have separate root and home partitions. If you combine them onto one this problem will go away.

Or, use a btrfs. With the root and home subvolumes in the same btrfs, the normal approach, the free space is pooled between them, and other subvolumes, if any.

[rdonnelly]

Yes I do have / and /home on separate partitions.
I will try all of your suggestions.
Thank You

[rdonnelly]

I would check /boot to make sure there's two kernels (vimlinuz*, initrd.img*, and System.map*). Sometimes I've had kernels get left behind by a release upgrade. The space taken up by such a kernel is mostly not in /boot but /usr; if you have got an old kernel that shouldn't be there use apt (or your favourite apt tool, mine's muon) to remove it.

I have 3 of each vimlinuz*, initrd.img*, and System.map*. I knew how to remove excess kernels in Mint, but not sure how to do it in Kubuntu?
By running the suggested commands, I now have 2.6 GB of free space.

[jglen490]

Typically, you should get notices of available updates. Some of those updates will be kernel updates.

There are ways to process kernel updates, but what I do is when Discover pops a notice of available changes, I go to a konsole and enter:

sudo apt update

sudo apt full-upgrade

If a kernel update occurred, after the next boot I'll run:

sudo apt autoremove

sudo apt autoclean

sudo apt clean

After that cycle I'm left with two kernels. If you manually install kernels for your own purposes, you will have to manually remove any old ones that you no longer need.

[rdonnelly]

Thanks Jglen

I notice Mozilla Firefox likes to put a lot on files in /tmp. Anyway to make it write to /home instead?

[claydoh]

You might be surprised at what takes up space, depending on what software you have installed, and even what types of packages you might have.

When I get stumped on this topic, I usually pull out Filelight and visually look at what is using space.
I was using flatpak to use VLC as the stock one was giving me fits, so I was testing specifically using a sandboxed format. I think that thie porogram, plus all its repo caches and dependencies were taking 3.1gb. Just for VLC, I tested and checked. Granted, the dependency sub-packages are shared with other applications if one installs a fair number of them, so it may not be a a true 'bloat' situation, particularly if those are Gtk/Gnome apps. VLC on a KDE Plasma system installed this is way is pure Bloaty McBloatface

Note that uninstalling one of these containerized applications does NOT necessarily uninstall any of its dependency sub-packages, though VLC via flatpak did remove all its extras. Not all seem to.

[rdonnelly]

Thanks, I will give Filelight a try. I have a lot of /var logs, do I need them?

[jglen490]

I use FF. So I looked in /tmp and /var/tmp. In few smallish files in both, and almost all were written during boot and login. The only place FF writes is to cache in /home, as far as I can tell.

So maybe the next question is, where did your FF come from?

[rdonnelly]

I use the FF that came with Kubuntu, or the package manager.

[rdonnelly]

I deleted a bunch of /var logs, now I have 6.2 GB free. All is well now.