hidden snapshots

English Install/Boot/Login
1

I’m running Tumbleweed, which was installed with the filesystem defaults, so I have a 40GB BTRFS root partition. That partition has now only 1GB of free space, so I can’t do a system update

In the past when I’ve had space problems on the root partition, it’s been because of accumulated snapshots, so I ran snapper:


laura:/home/laura # snapper list         
 # | Type   | Pre # | Date | User | Cleanup | Description | Userdata
---+--------+-------+------+------+---------+-------------+---------
0  | single |       |      | root |         | current     |

However, listing /.snapshots directly gives:


laura:/home/laura # ls -la /.snapshots
total 20
drwxr-x--- 1 root root  52 Dec 29 13:57 **.**
drwxr-xr-x 1 root root 512 Oct  5  2018 **..**
drwxr-xr-x 1 root root  16 Nov 19 11:08 **2**
drwxr-xr-x 1 root root  38 Mar  4  2016 **55**
drwxr-xr-x 1 root root  38 Mar  4  2016 **56**
drwxr-xr-x 1 root root  52 Jun 14  2017 **70**
drwxr-xr-x 1 root root  52 Jun 14  2017 **73**
-rw-r----- 1 root root 184 Dec 29 13:57 grub-snapshot.cfg

And looking at the disk usage gives:


laura:/home/laura # btrfs filesystem du -s /.snapshots/*
     Total   Exclusive  Set shared  Filename
  28.30GiB     5.92GiB    22.38GiB  /.snapshots/2
     0.00B       0.00B       0.00B  /.snapshots/55
     0.00B       0.00B       0.00B  /.snapshots/56
   4.83MiB     4.83MiB       0.00B  /.snapshots/70
     0.00B       0.00B       0.00B  /.snapshots/73
     0.00B       0.00B       0.00B  /.snapshots/grub-snapshot.cfg

which leads me to believe that the phantom snapshot 2 might be the cause of my problems

I can’t use snapper to delete any of the listed snapshots, e.g.

laura:/home/laura # snapper delete 2
Snapshot '2' not found.

But when new snapshots are created, the first is numbered ‘1’ and the second is numbered ‘3’, so it recognises that ‘2’ is there

How do I get rid of the hidden snapshots? Can I just manually delete the subdirectories from /.snapshots? Can I check that the 28.3GB isn’t live data? How do I avoid getting in this situation again?

Any help greatly appreciated

TIA
Laura

2

Hi
That’s how snapshots work, it’s only consuming 5.92GiB… so have you run the btrfs maintenance tools to clean up manually (are the jobs running?)? Consider refining the snapshots kept vi editing /etc/snapper/configs/root to something that suits your needs.

For example;


systemctl status btrfs-balance.timer 
● btrfs-balance.timer - Balance block groups on a btrfs filesystem
   Loaded: loaded (/usr/lib/systemd/system/btrfs-balance.timer; enabled; vendor preset: enabled)
  Drop-In: /etc/systemd/system/btrfs-balance.timer.d
           └─schedule.conf
   Active: active (waiting) since Wed 2020-01-01 21:48:41 CST; 1 day 13h ago
  Trigger: Mon 2020-01-06 00:00:00 CST; 2 days left
     Docs: man:btrfs-balance

Jan 01 21:48:41 grover systemd[1]: Started Balance block groups on a btrfs filesystem.
3

Hi
Oh, don’t try and delete 2, that’s the running system… delete that and you will hose it… :wink:

4

You can’t use free memory; you only can use unallocated memory:

erlangen:~ # btrfs filesystem usage -T /
Overall:
    Device size:                  59.45GiB
    Device allocated:             15.03GiB
  **  Device unallocated:           44.42GiB**
    Device missing:                  0.00B
    Used:                         12.46GiB
    Free (estimated):             45.53GiB      (min: 45.53GiB)
    Data ratio:                       1.00
    Metadata ratio:                   1.00
    Global reserve:               37.22MiB      (used: 0.00B)

             Data     Metadata  System              
Id Path      single   single    single   Unallocated
-- --------- -------- --------- -------- -----------
 1 /dev/sdb5 13.00GiB   2.00GiB 32.00MiB    44.42GiB
-- --------- -------- --------- -------- -----------
   Total     13.00GiB   2.00GiB 32.00MiB    44.42GiB
   Used      11.89GiB 585.17MiB 16.00KiB            
erlangen:~ #

Advice for deallocating memory: BTRFS and free space - emergency response • Oh The Huge Manatee!

5

Like you see you can’t delete snapshots that snapper no longer sees. But … you can do this, replace 180 by the snapshot no you want to delete from disk


btrfs subvolume delete /.snapshots/180/snapshot/
cd /.snapshots
rm -rf  180