[Solved] Missing free space in root partition

syleus · 2020-11-11 15:25:34

Hello,

After upgrading my system, I have an issue with my root partition. I am missing 16G of free space over 50G of total space, and I haven't found any similar issue while browsing the internet (except whith the 5% root reserved, which I am well beyond).

Here is the output of df

[ulysse@syleus ~] df -h / 
Sys. de fichiers Taille Utilisé Dispo Uti% Monté sur
/dev/sda3           50G     34G     0 100% /

As you can see, although only 34/50 G are used, df report 100% disk space used, and any further run of pacman will stop due to a lack of space.

Here is my (messy) patitioning :

[ulysse@syleus ~] lsblk
NAME   MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
sda      8:0    0 119,2G  0 disk
├─sda1   8:1    0   260M  0 part /boot
├─sda2   8:2    0    16M  0 part
├─sda3   8:3    0    50G  0 part /
├─sda4   8:4    0  68,1G  0 part /home
└─sda6   8:6    0   871M  0 part
sdb      8:16   0 931,5G  0 disk
├─sdb1   8:17   0 488,3G  0 part
├─sdb2   8:18   0    16M  0 part
├─sdb3   8:19   0 277,9G  0 part
└─sdb4   8:20   0 165,3G  0 part /mnt/data

I do not even know how to investigate further; do you have any idea of what the cause would be, or any command that would help me pinpoint the issue here ?

Thanks in advance,

Last edited by syleus (2020-11-11 16:48:24)

WorMzy · 2020-11-11 15:35:24

What is the filesystem? Since you mention 5%, I'm guessing ext4, but please confirm.

syleus · 2020-11-11 15:39:21

Thanks for your reply, I just checked and it is in fact a btrfs partition, may it be the issue here ?

[ulysse@syleus ~] df -Th                                               { 20-11-11 - 16:36 }
Sys. de fichiers Type     Taille Utilisé Dispo Uti% Monté sur
dev              devtmpfs   3,9G       0  3,9G   0% /dev
run              tmpfs      3,9G    1,4M  3,9G   1% /run
--> /dev/sda3        btrfs       50G     34G     0 100% / <--
tmpfs            tmpfs      3,9G    200M  3,7G   6% /dev/shm
tmpfs            tmpfs      4,0M       0  4,0M   0% /sys/fs/cgroup
tmpfs            tmpfs      3,9G     12K  3,9G   1% /tmp
/dev/sda4        btrfs       69G     59G  8,9G  87% /home
/dev/sda1        vfat       260M     86M  175M  33% /boot
/dev/sdb4        ext4       162G    152G  2,3G  99% /mnt/data
tmpfs            tmpfs      793M     52K  792M   1% /run/user/1000

WorMzy · 2020-11-11 16:17:35

Only in the sense that df is an inappropriate tool for querying btrfs disk usage. See https://wiki.archlinux.org/index.php/Bt … free_space and https://wiki.archlinux.org/index.php/Btrfs#Balance

syleus · 2020-11-11 16:30:33

Oh, indeed. It seems that usign this suitable command report the correct free space.

[ulysse@syleus ~] sudo btrfs filesystem usage /
[sudo] Mot de passe de ulysse :
Overall:
    Device size:		  50.00GiB
    Device allocated:		  50.00GiB
    Device unallocated:		   1.00MiB
    Device missing:		     0.00B
    Used:			  33.82GiB
    Free (estimated):		  16.10GiB	(min: 16.10GiB)
    Data ratio:			      1.00
    Metadata ratio:		      1.00
    Global reserve:		  74.23MiB	(used: 0.00B)
    Multiple profiles:		        no

Data,single: Size:49.24GiB, Used:33.14GiB (67.30%)
   /dev/sda3	  49.24GiB

Metadata,single: Size:776.00MiB, Used:698.52MiB (90.01%)
   /dev/sda3	 776.00MiB

System,single: Size:4.00MiB, Used:16.00KiB (0.39%)
   /dev/sda3	   4.00MiB

Unallocated:
   /dev/sda3	   1.00MiB

However, pacman still reports "partition full" when updating. I understand by your second link that the following command

btrfs balance start /

could potentially solve my issue.

I have a warning that this command will take a while to complete, i'll keep you updated in a bit.

Thanks again !

syleus · 2020-11-11 16:47:20

So, unfortunately, the last command ended up very soon in

ERROR: error during balancing '/' - No space left on device

Investigating further, I found this thread, and what I ended up doing is

- deleting a big unused folder (in my case /opt/anaconda, laying there after an unfinished and failed install)

- then running

sudo btrfs fi balance start -dusage=10 /

For future reference, if having the same issue and unwilling to delete any file in the partition, the link above mentions a way of getting around, referencing the following blog : http://marc.merlins.org/perso/btrfs/pos … blems.html

This thread is now solved, thanks again for your help.

Last edited by syleus (2020-11-11 16:48:43)

Arch Linux

#1 2020-11-11 15:25:34

[Solved] Missing free space in root partition

#2 2020-11-11 15:35:24

Re: [Solved] Missing free space in root partition

#3 2020-11-11 15:39:21

Re: [Solved] Missing free space in root partition

#4 2020-11-11 16:17:35

Re: [Solved] Missing free space in root partition

#5 2020-11-11 16:30:33

Re: [Solved] Missing free space in root partition

#6 2020-11-11 16:47:20

Re: [Solved] Missing free space in root partition

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