So the installer gets it wrong… automagically. 
Not wrong. Just not optimal.
The Installer’s Way:
- Enable CoW and checksums across the entire volume
- Set one exception for the swap file
Everything I’ve read says just make the whole swap subvolume nodatacow.
I bet they probably perform about the same. But it made sense to me that this way is better, it’s just cleaner isolation. (And saves you a command 
. ) Prevents snapshots and everything you don’t want as well.
(But I’ll never know, I only use partitions! hah.)
2 Likes
First line mounts the subvolume, the second mounts the file in the subvolume to swap? Or maybe they do the same thing..
/swapp/swapfile none swap defaults 0 0
sudo lsattr -l
./swapfile No_COW
I didn’t do it manually, I think the command to create the swap file did it.
Indeed, it did. That’s exactly what that command does. It creates a file using mkswap, and then disables compression and copy-on-write on the file.
2 Likes
So, since the swapfile is in a subvolume and has nocow everything is good, right? It could be better creating a swap partition, but it’s a story for another time.
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Before, this landed on your @ volume. But I assume you have the proper mount working now..
findmnt /swap– Handy command with btrfs and mounts
Sorry, I mean swapp.
What’s with the extra p anyway?
I guess I’m just not cool enough to have /roott and /swapp.. 
It was on sale this week. 
2 Likes
Gives no output
I have a LOT of extra p, if you need some I’ll hook you up, I mean, uppp
(1/1) Creating Timeshift snapshot before upgrade...
Using system disk as snapshot device for creating snapshots in BTRFS mode
Mounted '/dev/nvme0n1p2' (subvolid=0) at '/run/timeshift/2048/backup'
btrfs: Quotas are not enabled
Creating new backup...(BTRFS)
Saving to device: /dev/nvme0n1p2, mounted at path: /run/timeshift/2048/backup
Created directory: /run/timeshift/2048/backup/timeshift-btrfs/snapshots/2026-02-12_13-22-57
Created subvolume snapshot: /run/timeshift/2048/backup/timeshift-btrfs/snapshots/2026-02-12_13-22-57/@
Created subvolume snapshot: /run/timeshift/2048/backup/timeshift-btrfs/snapshots/2026-02-12_13-22-57/@home
Created control file: /run/timeshift/2048/backup/timeshift-btrfs/snapshots/2026-02-12_13-22-57/info.json
BTRFS Snapshot saved successfully (0s)
Tagged snapshot '2026-02-12_13-22-57': ondemand
------------------------------------------------------------------------------
Detecting snapshots ...
Found snapshot: 2026-02-12 13:22:57 | timeshift-btrfs/snapshots/2026-02-12_13-22-57/@ | ondemand | {timeshift-autosnap} {created before upgrade} |
Found snapshot: 2026-02-12 00:00:01 | timeshift-btrfs/snapshots/2026-02-12_00-00-01/@ | daily | N/A |
Found snapshot: 2026-02-11 00:00:00 | timeshift-btrfs/snapshots/2026-02-11_00-00-00/@ | daily | N/A |
Found snapshot: 2026-02-10 00:00:01 | timeshift-btrfs/snapshots/2026-02-10_00-00-01/@ | daily | N/A |
Found snapshot: 2026-02-08 19:24:23 | timeshift-btrfs/snapshots/2026-02-08_19-24-23/@ | ondemand daily | {timeshift-autosnap} {created before upgrade} |
Found snapshot: 2026-02-08 12:55:05 | timeshift-btrfs/snapshots/2026-02-08_12-55-05/@ | ondemand | Manualmente |
if [ ! -e "${prefix}/grub-btrfs.cfg" ]; then
echo ""
else
submenu 'Manjaro Linux snapshots' {
configfile "${prefix}/grub-btrfs.cfg"
}
fi
Found 6 snapshot(s)
Unmount /tmp/grub-btrfs.gzgkf9xqsI .. Success
:: Elaborazione delle modifiche al pacchetto...
(1/1) aggiornamento in corso di manjaro-kde-settings [################################################] 100%
Nuove dipendenze opzionali di manjaro-kde-settings
sddm-breath-theme [installato]
:: Esecuzione degli hook di post-transazione...
(1/1) Arming ConditionNeedsUpdate...
There’s some code in the output; automatic snapshot creation seems to work
This is where you need the extra p. (Where you mounted it.)
findmnt /swapp
You should see a SOURCE of something like:/dev/..p2[@swapp] and then all the other mount options like subvol=/@swapp,notdatacow(if you used it), to see if it’s correct.
2 Likes
I did add the extra p in konsole, I have no output (even as root).
swapon --show
NAME TYPE SIZE USED PRIO
/swapp/swapfile file 16G 0B -1
findmnt /swapp
findmnt /swapp/swapfile
I’m still mounting the file, not the subvolume in fstab, like before.
If you don’t mount /swapp before creating the swap file, it won’t be in that specific subvolume. Obviously, you haven’t followed the instructions precisely enough.
There’s a difference between storing the file in the / subvolume or in /swapp.
You must first delete the file, then mount the subvolume, then recreate the file, and then correct the fstab file. Otherwise, you risk corrupting the file system or the swap file.
This is one of the reasons why a swap partition is preferred by many professionals.
3 Likes
Andreas is right.
And blank just means there’s no mount assigned to it.
What’s is your fstab line for @swapp? I know I suggested one for you a few posts back.
When troubleshooting mounts from your/etc/fstab, you can simply..
sudo mount /swapp
# Run test
sudo umount /swapp
It should mount automatically next reboot if the above works properly.
(And you need to make the swap file when it’s properly mounted.)
2 Likes
My subvolume is called swapp with 2 p because I had a folder called swap, so to be sure I added the extra p, I didn’t create a folder and named it swapp, I opened dolphin, went to /, right click, open terminal here (yes I like to use the GUI when possible) and then gave those commands exactly (except the path and size) as in the wiki
As I said before, I did it like the wiki, so I mount the file like this:
/swapp/swapfile none swap defaults 0 0
The file has nocow.
I asked if I should mount the subvolume and then the file like this example
or like this
or leave as it is now.
My subvolumes are
sudo btrfs subvolume list -t / 1 ✘
[sudo] password di acca:
ID gen top level path
-- --- --------- ----
257 16922 5 @home
258 16857 5 @cache
259 16922 5 @log
264 16922 5 @
276 16734 5 timeshift-btrfs/snapshots/2026-02-07_13-22-58/@
279 16734 5 timeshift-btrfs/snapshots/2026-02-08_12-55-05/@
280 14983 5 timeshift-btrfs/snapshots/2026-02-08_12-55-05/@home
281 16734 5 timeshift-btrfs/snapshots/2026-02-08_19-24-23/@
282 15027 5 timeshift-btrfs/snapshots/2026-02-08_19-24-23/@home
283 16758 264 swapp
284 16758 5 timeshift-btrfs/snapshots/2026-02-10_00-00-01/@
285 15558 5 timeshift-btrfs/snapshots/2026-02-10_00-00-01/@home
286 16758 5 timeshift-btrfs/snapshots/2026-02-11_00-00-00/@
287 15996 5 timeshift-btrfs/snapshots/2026-02-11_00-00-00/@home
288 16758 5 timeshift-btrfs/snapshots/2026-02-12_00-00-01/@
289 16255 5 timeshift-btrfs/snapshots/2026-02-12_00-00-01/@home
290 16758 5 timeshift-btrfs/snapshots/2026-02-12_13-22-57/@
291 16359 5 timeshift-btrfs/snapshots/2026-02-12_13-22-57/@home
292 16758 5 timeshift-btrfs/snapshots/2026-02-13_00-00-00/@
293 16734 5 timeshift-btrfs/snapshots/2026-02-13_00-00-00/@home
The last snapshot is from today and it backed @ and @home, not swap (I’m sure I’ve not needed swap yet)
The swap subvolume should not be snapshotted.
4 Likes
You need two lines in your fstab for this, one to mount the subvolume, then another for the swap file. You are missing the former.
So this swap file is landing on your root volume still.
This line. Where do you mount subvol @swapp?
Edit
Sorry, I just noticed this. That won’t work quite yet.
I thought we were on the same page, so I made some assumptions.
There’s two things wrong with swapp, it should be off the top level subvolume. And we should call it @swapp not swapp. (Technically we don’t have to, but just to follow convention.)
So you will need to delete that subvolume and create a new one.
As it’s not off the top level, let’s just delete it by ID:
sudo btrfs subvolume delete --subvolid=283 /
And create the proper subvolume:
sudo mount -o subvolid=5 /dev/nvme0n1p2 /mnt
sudo btrfs subvolume create /mnt/@swapp
Now, that second fstab entry should work!
2 Likes
It’s okay to do things in the GUI.
But please note that sometimes a recipe is intentionally designed not to work in the GUI because some steps require additional parameters, or because the GUI tools handle things differently.
2 Likes
Sorry I’ve been busy.
I’ve deleted the line from fstab, rebooted then:
sudo btrfs subvolume list -t /
ID gen top level path
-- --- --------- ----
257 20811 5 @home
258 20801 5 @cache
259 20811 5 @log
264 20811 5 @
279 20595 5 timeshift-btrfs/snapshots/2026-02-08_12-55-05/@
280 14983 5 timeshift-btrfs/snapshots/2026-02-08_12-55-05/@home
281 20595 5 timeshift-btrfs/snapshots/2026-02-08_19-24-23/@
282 15027 5 timeshift-btrfs/snapshots/2026-02-08_19-24-23/@home
290 20595 5 timeshift-btrfs/snapshots/2026-02-12_13-22-57/@
291 16359 5 timeshift-btrfs/snapshots/2026-02-12_13-22-57/@home
304 20595 5 timeshift-btrfs/snapshots/2026-02-19_23-00-00/@
305 19094 5 timeshift-btrfs/snapshots/2026-02-19_23-00-00/@home
306 20595 5 timeshift-btrfs/snapshots/2026-02-20_22-01-04/@
307 19161 5 timeshift-btrfs/snapshots/2026-02-20_22-01-04/@home
308 20593 5 timeshift-btrfs/snapshots/2026-02-21_23-00-00/@
309 19615 5 timeshift-btrfs/snapshots/2026-02-21_23-00-00/@home
310 20593 5 timeshift-btrfs/snapshots/2026-02-22_23-00-00/@
311 20100 5 timeshift-btrfs/snapshots/2026-02-22_23-00-00/@home
312 20593 5 timeshift-btrfs/snapshots/2026-02-23_23-00-01/@
313 20595 5 timeshift-btrfs/snapshots/2026-02-23_23-00-01/@home
314 20807 5 @swapp
UUID=ecbc0f71-e2df-4c2c-85a1-b83c7000eab8 /swapp btrfs subvol=/@swapp,nodatacow,noatime 0 0
/swapp/swapfile none swap defaults 0 0
I’ve deleted the /swapp folder and the swapfile, as you know I have a lot of extra p so the new subvolume is still called swapp
Just did this, I should reboot.
Now it’s off the top level (subvolid=5), perfect.
You just have to mount the volume and enable swap. But that works too.
sudo systemctl deamon-reload
sudo mount /swapp
sudo swapon /swapp/swapfile
Or..
reboot
2 Likes
I make sure to have none, when I go out.
But why the unnecessary p swap is a proper description.
2 Likes
Yes, it’s always best to go before you go. 
1 Like