Arch Linux

amdj

Member

Registered: 2019-03-01

Posts: 6

BTRFS Filesystem full, no subvolumes, no snapshots

I have a btrfs filesystem mounted on root, which says

# btrfs fi usage -T /
Overall:
    Device size:                 223.37GiB
    Device allocated:            220.04GiB
    Device unallocated:            3.33GiB
    Device missing:                  0.00B
    Used:                        216.91GiB
    Free (estimated):              4.78GiB      (min: 4.78GiB)
    Data ratio:                       1.00
    Metadata ratio:                   1.00
    Global reserve:              479.66MiB      (used: 0.00B)

                         Data      Metadata System
Id Path                  single    single   single   Unallocated
-- --------------------- --------- -------- -------- -----------
 1 /dev/mapper/cryptroot 217.01GiB  3.00GiB 32.00MiB     3.33GiB
-- --------------------- --------- -------- -------- -----------
   Total                 217.01GiB  3.00GiB 32.00MiB     3.33GiB
   Used                  215.56GiB  1.34GiB 48.00KiB

However, when I try to find why my disk is full, it says only that I have ~ 160G of used space:

# du -x -d1 /

141G    /home
0       /mnt
51M     /root
0       /srv
11M     /etc_old
6.0G    /var
25M     /etc
13G     /usr
768M    /opt
160G    /
160G    total

I cannot find what makes the drive full. There are two subvolumes:

# btrfs subvolume list /
ID 465 gen 297313 top level 5 path var/lib/portables                                                                                                        
ID 466 gen 297313 top level 5 path var/lib/machines  

but the directory contents of them is empty. I already tried to balance the filesystem with a

btrfs balance start -dusage=90 -musage=90 /

, but that only let to 2GB of reclaimed space. Does anybody know where the space is gone, or know a way to find out? Thanks in advance.

der_joachim

Member

From: the Netherlands

Registered: 2008-12-17

Posts: 143

Website

Re: BTRFS Filesystem full, no subvolumes, no snapshots

Do you use snapper? If so, how much space do your snapshots take up?

---

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WorMzy

Forum Moderator

From: Scotland

Registered: 2010-06-16

Posts: 11,868

Website

Re: BTRFS Filesystem full, no subvolumes, no snapshots

Mount the partition to /mnt and run du without -x against that mount point.

e.g.

# mount /dev/mapper/cryptroot /mnt
# du -hd1 /mnt

---

Sakura:-
Mobo: MSI MAG X570S TORPEDO MAX // Processor: AMD Ryzen 9 5950X @4.9GHz // GFX: AMD Radeon RX 5700 XT // RAM: 32GB (4x 8GB) Corsair DDR4 (@ 3000MHz) // Storage: 1x 3TB HDD, 6x 1TB SSD, 2x 120GB SSD, 1x 275GB M2 SSD

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amdj

Member

Registered: 2019-03-01

Posts: 6

Re: BTRFS Filesystem full, no subvolumes, no snapshots

Do you use snapper? If so, how much space do your snapshots take up?

No I don't use snapper, and I do not have any filesystems snapshots. If I am correct they would also show up in the subvolume list.

amdj

Member

Registered: 2019-03-01

Posts: 6

Re: BTRFS Filesystem full, no subvolumes, no snapshots

Mount the partition to /mnt and run du without -x against that mount point.

e.g.

# mount /dev/mapper/cryptroot /mnt
# du -hd1 /mnt

I did what you asked:

# cd /mnt
# mkdir cr
# mount /dev/mapper/cryptroot cr
# du -hd1 cr
1.7M    cr/boot
140G    cr/home
0       cr/mnt
51M     cr/root
0       cr/srv
6.0G    cr/var
0       cr/dev
0       cr/run
25M     cr/etc
0       cr/tmp
0       cr/sys
0       cr/proc
13G     cr/usr
768M    cr/opt
160G    cr
160G    total

No difference.

Last edited by amdj (2019-03-27 08:43:00)

willemw

Member

Registered: 2013-02-19

Posts: 113

Re: BTRFS Filesystem full, no subvolumes, no snapshots

/dev/mapper/cryptroot pre-allocates all its blocks (220GiB)?

amdj

Member

Registered: 2019-03-01

Posts: 6

Re: BTRFS Filesystem full, no subvolumes, no snapshots

I managed to make some space by running

# btrfs filesystem defrag - r -c <heavy folder here>

on some heavy folders. However, still the problem is there.

amdj

Member

Registered: 2019-03-01

Posts: 6

Re: BTRFS Filesystem full, no subvolumes, no snapshots

/dev/mapper/cryptroot pre-allocates all its blocks (220GiB)?

I am not exactly an expert on filesystem stuff, but if 216Gib is really used, it sounds reasonable to me that 220GiB is allocated?