Ok so quick update here: I was following the mount procedure from the first link and it's looking good! However, I started with a fresh installation instead of moving my files around, but seeing as it worked out, migrating an existing installation should be no problem either.

So what I did:

deployed a new Cloudron with Nextcloud installed on a fresh CPX21 on Hetzner Cloud (kept it at 40GB though, might scale down if performance allows it) mounted a 5TB Hetzner Storagebox via sshfs into /mnt/cloud and added it as Cloudron volume (/media/cloud) mounted that volume into the Nextcloud app (uncheck read-only) change the datadirectory in config/config.php from 'datadirectory' => '/app/data', to 'datadirectory' => '/media/cloud', cp -r /app/data/admin to the mounted volume and touch .ocdata in /media/cloud

That's pretty much it I reckon, if you log in now you have this extra storage available:
13da2c2f-cb18-48c9-b90c-950c44bf2770-grafik.png

I have both, uploaded a few GB manually and the rest via sync client, no errors so far. A restart won't change the datadirectory, so this should continue working after reboots. Encryption is also enabled and working as intended, still waiting for something that doesn't work properly.

Ok, I solved it. I had to delete all my DNS settings that previously existed and then reset them. Once I did this within milliseconds Cloudron started working.

Whew, I was sweating bullets there for a minute.

@nebulon I find the solution taking infos from this forum .

In fact, I opened port 53 TCP and UDP and Cloudron can resolve domain names.

Configuration now is:

firewall template.png

All seems to working fine... I marked this thread as "Solved" 🙂

@nebulon Yes before rebooting I tried to umount-remount but it seems it has been impossible due to an error... So I decided to restart.

About auto-remounting it will be an amazing feature

This could come in handy for the selfhost.cloud stuff @thetomester13 and I are working on 🙂

@mehdi Not sure I know enough yet about handling updates, patches & security so just running in good faith on all that at the mo.

Happy? Yes.

Confident? Sure - until something goes wrong 🙂

Just always thinking about prevention being better than cure.

Ok I gotcha myself because anyway I create my own pain 😉

so from what I understand
to being able to restore Cloudron verify the DNS first than app/data

I forgot to authorize my new IP in my Cloudflare API

code 9109 is probably related to the fact it was unable to edit the DNS.

correct in your case this should not be any issue as this is mounted like a regular ext4 which supports hardlinks just fine.

To know the backup scope, you can sum up all the apps listed there + email data + box data. Then you would have to multiple that by the number of backups which are stored (eg. once every day for 1 week or so) This would be the maximum of storage required using the tarball method. For rsync, it would be much less since it would do incremental backups.