My setup for context:

• cloudron: a hetzner auction server with mixed HDD+SDD
• backup box: a storage VPS in a different geographical location, using SSHFS (encrypted rsync)
  • had a good experience with this so far, the ability to use hardlinks is a game changer for storage size, as well as not being charged per request
  • requires manually setting up a secure ssh box. I used unattended-upgrades and ufw
  • for peace of mind, i also do an offline manual backup to a drive at home every ~3-6 months
• Mixed HDD+SSD was useful for keeping cost low while balancing the needs of large apps like Nextcloud vs most other apps on cloudron. I haven't had much luck mounting external storage, so liked the idea of a bigger drive locally. the deal i found happened to have 3 drives and i laid them out like this
  • 2x512GB SSD with RAID1; default drive mounted at /, for apps where i care about both uptime & speed (email,websites..)
  • 1x1TB SSD; less critical apps where i care about speed, media-heavy apps like immich
  • 1x2TB HDD; large storage apps (Nextcloud)
  • I haven't yet set up email RAID monitoring if anyone has advice there

Before the migration i had to

• partition drives, mount extra SSD and HDD in /etc/fstab, set up RAID
• whitelist ip of the new server in my domain provider's API if needed. this was the case for namecheap.
• note down my ssh private key from the backup user (normally in /home/yellowtent/ssh) on the old server before powering it down. the backup config file doesn't include this automatically.
• i think it's best to harden SSH and firewall after fully completing restore. i tried to do this after installing cloudron but before restoring via the web interface, but seemed to always run into issues. not sure if other people have had this experience.

I ran into an issue where on my root 0.5TB drive, nextcloud would not fit. there wasn't a clear way to assign a data directory for it in advance of restore, so i had to restore it on a per-app basis via the following:

• start the restore via https://your-new-ip
• wait until the dashboard is up
• mount additional drives as volumes (i used filesystem(mountpoint)). I believe currently mounting them in /etc/fstab does not automatically make them recognized within cloudron.
• go to large app->uninstall menu->Archive
  • there didn't seem to be a way to pause the restore, or change data directory while running the restore, so this was the only way i found to prevent completely filling my drive. after a while when restore for other apps finished, this app was left in Error state and I could then successfully archive on the second attempt.
  • download app backup config from backups->archive
• install new instance of large app from the appstore that matches the backup app version
  • download a specific version of an app by changing the appstore URL: ie https://my.server.com/#/appstore/com.nextcloud.cloudronapp?version=5.5.2 <-- change to version=x.x.x
• move this app's data directory to the volume where your additional drive is mounted (app settings->storage->data directory)
• import app backup using the config file downloaded earlier

Curious how other's experience has been with large migrations, if you've found easier ways. Also your server/backup setups for dealing with apps like Nextcloud. I think some of this process can be improved or clarified in documentation/error messages. I.e. a note to remember to whitelist new server IP in domain provider API.

Having an option to mount volumes and assign per-app data-directory as part of the restore wizard would be fantastic.