Creating snapshot failed (Snapper, systemd-boot, btrfsassistant)

General system Applications
1

I am using Snapper with Btrfs Assistant and Systemd-boot with no issues since more than one year. Two days ago I performed a new installation on a new computer. (I also copied a part of my .config files, if it is a usefull info).
Anyway, Btrfs assistant was installed with no issue, as the needed snapper packages. I created a default “root” config for snapper within btrfs assistant, as usual. It was created, but no snapshot is created.
When I try to manually create one I get the message “Creating snapshot failed”.
Any idea how to debug this ?

This is the result of sudo btrfs sub list

ID 256 gen 6750 top level 5 path @
ID 257 gen 6750 top level 5 path @home
ID 258 gen 6710 top level 5 path @cache
ID 259 gen 6750 top level 5 path @log
ID 260 gen 6676 top level 5 path @swap
ID 261 gen 6676 top level 256 path var/lib/portables
ID 262 gen 6676 top level 256 path var/lib/machines
ID 266 gen 6750 top level 256 path .snapshots

And the message I get in Btrfs assistant

Screenshot_26-03-12_1808-20
Screenshot_26-03-12_1808-20600×293 44 KB

Any help appreciated…. (@dalto ?)

2

Maybe I should ad that from within Btrfs assistant, /.snapshot appears as @/.snapshots

Screenshot_26-03-12_1816-54
Screenshot_26-03-12_1816-54500×340 52.8 KB

3

What happens if you use snapper in the cli to create a snapshot

4

I get “No permissions”
And with sudo (sudo snapper create), same message as in Btrfs assistant: Creating snapshot failed

5

From the last boot log:

Mar 12 17:41:55 PP-EOS systemd[1]: Failed to start Take snapper snapshot of root on boot.
░░ Subject: A start job for unit snapper-boot.service has failed
░░ Defined-By: systemd
░░ Support: https://lists.freedesktop.org/mailman/listinfo/systemd-devel
░░
░░ A start job for unit snapper-boot.service has finished with a failure.
░░
░░ The job identifier is 1335 and the job result is failed.

6

I have also tried with different kernels (Arch and Lts) , but it’s the same.

7

Yeah, you definitely need sudo.

Can you share findmnt --real

8 
TARGET  SOURCE  FSTYPE OPTIONS 
/       /dev/nvme0n1p2\[/@\] 
│               btrfs  rw,noatime,compress=zstd:3,ssd,discard=async,space 
├─/home /dev/nvme0n1p2\[/@home\] 
│               btrfs  rw,noatime,compress=zstd:3,ssd,discard=async,space 
├─/swap /dev/nvme0n1p2\[/@swap\] 
│               btrfs  rw,noatime,compress=zstd:3,ssd,discard=async,space 
├─/run/media/ptah/Archives-SSD 
│       /dev/sdc1 
│               ext4   rw,nosuid,nodev,relatime,errors=remount-ro,stripe= 
├─/run/media/ptah/Backup-Main 
│       /dev/sde1 
│               ext4   rw,nosuid,nodev,relatime,errors=remount-ro,stripe= 
├─/run/media/ptah/fifo1x 
│       /dev/sdd1 
│               ext4   rw,nosuid,nodev,relatime,errors=remount-ro,stripe= 
├─/run/media/ptah/Music-4Tb 
│       /dev/sdb1 
│               exfat  rw,nosuid,nodev,relatime,uid=1000,gid=1000,fmask=0 
├─/run/media/ptah/Series-4Tb 
│       /dev/sdf1 
│               ext4   rw,nosuid,nodev,relatime,errors=remount-ro 
├─/var/cache 
│       /dev/nvme0n1p2\[/@cache\] 
│               btrfs  rw,noatime,compress=zstd:3,ssd,discard=async,space 
├─/var/log 
│       /dev/nvme0n1p2\[/@log\] 
│               btrfs  rw,noatime,compress=zstd:3,ssd,discard=async,space 
└─/efi  /dev/nvme0n1p1 
                vfat   rw,relatime,fmask=0137,dmask=0027,codepage=437,ioc
9

How about sudo ls -a /.snapshots

10

It doesn’t return anything. Only . ..

11

Make sure you don’t have a swapfile in / somewhere

12

Humm…. This is my fstab
# <file system> <mount point> <type> <options> <dump> <pass>
UUID=B868-A656 /efi vfat fmask=0137,dmask=0027 0 2
UUID=2a17dd6d-ee07-4d53-959b-0215abf4903d / btrfs subvol=/@,noatime,compress=zstd 0 0
UUID=2a17dd6d-ee07-4d53-959b-0215abf4903d /home btrfs subvol=/@home,noatime,compress=zstd 0 0
UUID=2a17dd6d-ee07-4d53-959b-0215abf4903d /var/cache btrfs subvol=/@cache,noatime,compress=zstd 0 0
UUID=2a17dd6d-ee07-4d53-959b-0215abf4903d /var/log btrfs subvol=/@log,noatime,compress=zstd 0 0
UUID=2a17dd6d-ee07-4d53-959b-0215abf4903d /swap btrfs subvol=/@swap,noatime 0 0
/swapfile swap swap defaults 0 0
tmpfs /tmp tmpfs defaults,noatime,mode=1777 0 0

I do have a swap… Shall I delete it ?

13

Yeah, that is the issue.

Your swapfile needs to be inside /swap, so /swap/swap

You can’t take snapshots of a subvolume with a swapfile in it.

14

Wow, it works !!! Many thanks :folded_hands: