Not enough space on /tmp

What seems to have happened:

Your / was full, then Ubuntu created a new partition, in RAM memory, to use temporarily.

Now, this 1MB partition is not big enough for the job, either.

What we can do:

1) increase the size of this partition just to do the upgrade

2) actually delete enough files in the HD that this partition is no longer needed.

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To do 1:

open a terminal and run

sudo umount /tmp
sudo mount -t tmpfs -o size=1048576,mode=1777 overflow /tmp

This should give you an 1MB partition (just like the one you had =P).

Now, to increase the size, you increase the size in that line, so that, with size=10485760, you'd get 10 MB.

Your goal is to find a number that is enough for the job, but leaves enough ram too

Comments on 1

You may want to try sudo umount -l /tmp, if you get some variation of "the file system is busy and cannot be unmounted"

Another possible solution to "the file system s busy(...)" is to do fuser -m /tmp to find pids (process numbers) that are using /tmp, then ps -elf <pids>, stop or kill processes

You may want to try sudo mount -t tmpfs -o size=1MB,mode=1777 overflow /tmp or even sudo mount -t tmpfs -o size=1G,mode=1777 overflow /tmp (for 1 megabyte or 1 gigabyte, respectively) - that is, units are available so that you dont have to type a huge number

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To do 2:

Open a terminal and run sudo umount /tmp or, if that fails, sudo umount -l /tmp.

Then clean up!

Delete files in /tmp (now /tmp is the thing actually in your HD, rather than a virtual ram disk), uninstall unused packages, delete files in your home folder and so on.

I know about this problem on my Kubuntu 16.04, and user63070 shows the best answer. Change the size at /etc/fstab like this:

tmpfs     /tmp     tmpfs     defaults,size=10G,mode=1777     0     0

Reboot, and you got 10GB for your /tmp folder.

sudo mount -o remount,size=1048576 /tmp

changes tmpfs size without need to unmount partition and hence not disturbing running apps.