My /boot/efi/ became 100% full suddenly and this is how I resolved the issue

2020-09-25   4 min read

As the title says - a while ago I was doing something with my operating system Pop!OS and voila, all of a sudden my laptop threw me a pop up saying something like 'low disk capacity - /boot/efi 100% full, 0MB available'. Wow, thanks, that sounds quite alarming and not very fun. In fact, the Internet told me that /boot/efi has very much to do with rebooting and I did not want my computer to be a useless plastic brick, so intead of putting it off I decided to deal with it immediately, which did make me feel like I was finally a competent adult.

Contents

  • How I identified the cause of the issue
  • Fix
  • Thoughts

(1) How I identified the cause of the issue

First I checked what's filling up /boot/efi. So ran du -h in /boot and the result was below df -th result

At this point, I was looking for a file/system that was around 200MB because I luckily remembered that last time I had seen the disk usage situation, /boot/efi was around 60% full. As shown in the image, /boot/efi/ was 100% full of 522MB. That means whatever used to not exist in /boot/efi is likely to be 200MB(= 522MB * 0.4).

So I took a look at what exactly was in each directories.

disk usage in boot

Okay, the contents of Pop_OS-df28e3aa-886a-4bda-8ecf-a0ffbf0a34d2 and Ubuntu-df28e3aa-886a-4bda-8ecf-a0ffbf0a34d2 look... kind of the same, at least from outside. So I ran ls -lh to see if they are really the same size.

compare what is in ubuntu and popos

Alright, looks like Ubuntu-df28e3aa-886a-4bda-8ecf-a0ffbf0a34d2 was created almost at the same time as /boot/efi got full and it was indeed 188MB which explained my math.

(2) Fix

I did't need 2 pairs of cmdline initrd.img initrd.img-previos vmlinuz.efi vmlinuz-previous.efi and apparetnly those in Ubuntu-df28e3aa-886a-4bda-8ecf-a0ffbf0a34d2 were missing some file contents that were in Pop_OS-df28e3aa-886a-4bda-8ecf-a0ffbf0a34d2. I decided to remove the whole Ubuntu-df28e3aa-886a-4bda-8ecf-a0ffbf0a34d2.

To do so, I ran rm -rf Ubuntu-df28e3aa-886a-4bda-8ecf-a0ffbf0a34d2 which cleared 37% of /boot/efi space.

Disk usage after fix

Just to make sure my machine would reboot properly without the files I just had deleted, I rebooted it and it indeed did reboot. Phew!

(5) Useful resources

These recourses helped me connect each dots of my knowledge as I am no OS expert nor a cs grad.

How to edit /boot/efi

https://askubuntu.com/questions/650291/how-to-edit-boot-efi

What is the efi/esp partition?

https://askubuntu.com/questions/659588/what-is-the-efi-esp-partition

cd into directory without having permission

https://stackoverflow.com/questions/8221820/cd-into-directory-without-having-permission

Why doesn't sudo cd /var/named work?

https://askubuntu.com/questions/291666/why-doesnt-sudo-cd-var-named-work

EFI Partition vs /boot partition

https://superuser.com/questions/520068/efi-partition-vs-boot-partition)

What is UEFI Secure Boot?

https://wiki.ubuntu.com/UEFI/SecureBoot

UEFI boot: how does that actually work, then?

https://www.happyassassin.net/posts/2014/01/25/uefi-boot-how-does-that-actually-work-then/

What are initrd.img* files?

https://www.reddit.com/r/linuxquestions/comments/e05tmf/what_are_initrdimg_files/


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