/ Full Root Partition - tip for manage temporal files (also Nuke tip) on Linux Centos

(updated September 2022)

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A fast way to avoid full root partion due to lack of space on older Centos.

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/ First look

If you use automatic partitions on installing Linux Centos you get annoying messages soon about being full on /root .

On my workstation it was set around 50 Gb.

df / -h

/dev/mapper/cl-root   50G   28G   23G  55% /

Sooner or later you would need to search a way to resize your /root which is irritating.

So I wanna share a small TIP. This way you wouldnt need to resize anything.

/ Check your troublemakers first:

First of all you must look as superuser whose are the main folders you use to get full recursively:

du -h --max-depth=1

If you prefer a graphic way use as user:

babobab

This way you can see graphically which are the most heavy folders that need to be cleened up.

View fullsize

Usually you will notice some folders whose are recursively filled by data and you need to recursively empty from time to time.
The global temporary directories are /tmp and /var/tmp

I use to play a comand for empty this files

rm -rf ~/.local/share/Trash/*

rm -rf ~/tmp/*

etc

But again an againg you lost your time removing trash so, what Ive done is very simple:

This is useful but just for temporal or shared folders, caches, etc. ; not a great idea for important root folders as it can do some damage or vulnerability to the system (you will see on rebboting).

I just use it when some apps download their cache data to root partition instead of my default user; this use to happen on installing as root or by managing preferences in a bad way.

A good example: Firefox downloads and Firefox cache. You can set up your download directory in preferences,
but there is also a caché folder which goes to /tmp/mozilla_user0 so I use my tip on this one also. When I dowload a lot of data I don’t want to full my root drive.

So now we go to a very simple tip:

/ TIP, move /tmp folder to another disk:

Look for your /tmp folder from your root partition.

/tmp

Copy that tmp folder at your /Documents or any place you prefer, or create one from scratch.

/home/user/Documents/temporalRoot/tmp

Create a “tmp” folder alias (dynamic link in linux) and place it where root use to have the original folder.
You will need first to delete the original one in /.
As simple as it is: you are linking the data to other drive area.

Finally manage permissions by chmod 775 or whatever you need.

chmod 775  /home/user/Documents/temporalRoot/tmp

Generally there is some confusion about permissions, so you need to know:

There is a root folder (generally /tmp, which belongs to root)

There are other user folders (inside /tmp we can have user folders)

For example in case of Firefox, it will be the user folder, as it is user who has the right permissions (can write and delete, etc).

d rwx --- --- 2 user user mozilla_user0

In case of nuke folder should be similar: but due to license, nuke can be owner by user or root, so maybe you are running the app as user, but the real owner is root.

/ TIP for NUKE USERS:

When you run Nuke on first time, cache derivates to root device so usually this goes to /var/tmp/nuke-u100 so, any time you reinstall a new version you need to check that folder.

Very often this folder gets full and freezes your system while your /home user folder keeps being full of space.

I have a dynamic link on my root partition, so the temporal data goes to my home.

/home/user/Documents/TemporalRoot/nuke-u1000

Now my root partition use to get enough space and I can empty my temporal folders as non root user.

In case Nuke crashes or you would get an update, your cache won’t fill your /root partition if you forget to set up the preferences, because it will always search this folder.

I setup my permisses on this nuke-u1000 for my Owner User Create and delete, Group User can Access files and Others can also Acces files. This way just Nuke User and Root can write on this folder. As general rule Nuke use to be instaled as User.

You can check your nuke default cache location in your preferences.

Nuke default cache location

Linux and macOS:

"/var/tmp/nuke-{uid}/" 

where {uid} is the users user ID on the machine, e.g. /var/tmp/nuke-u1737/

And here a reminder about permissions:

rwx = 111 in binary = 7

rw- = 110 in binary = 6

r-x = 101 in binary = 5

r-- = 100 in binary = 4

/ BONUS TIP: remove old kernels

As additional tip you can also remove all older kernels.

Centos keeps updating all the time, so at the end of the year you have lots of updates filling space. A way to clean them up is typing the next commands:

# list actual kernel
uname -a

# list older kernels
rpm -q kernel
# list more detailed
dnf list installed kernel

# remove all except latest 1
package-cleanup --oldkernels --count=1
# remove kernel version manually
sudo dnf remove kernel-5.14.0-70.13.1.el9

# automatic remove (Rocky)
sudo dnf install dnf-automatic

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