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SSH keys

Mnemosynce uses SSH keys for two distinct purposes. Understanding which key does what will save you time when setting things up.

Two key roles

Key Used for Where it lives
Source key Pulling data from remote source machines (e.g. your desktop) Generated in the web UI, stored in /data/ssh/
Remote sync key Pushing the local backup to the remote storage host Hardcoded path: /root/.ssh/id_ed25519_backup

Source keys — managed in the web UI

Go to Settings → SSH Keys (or the SSH Keys step of the setup wizard).

Generating a key

  1. Enter a name — letters, numbers, hyphens, and underscores only (e.g. desktop_mark).
  2. Optionally add a comment (e.g. backup-server/desktop_mark).
  3. Click Generate.

The private key is saved to /data/ssh/<name> with mode 600. The public key is shown immediately.

Copying the public key to a remote host

After generating, copy the public key string displayed on screen and paste it into ~/.ssh/authorized_keys on the remote machine:

# On the remote machine (e.g. your desktop)
echo "ssh-ed25519 AAAA...rest-of-key..." >> ~/.ssh/authorized_keys

Or use ssh-copy-id from the backup server if you still have password access:

ssh-copy-id -i /data/ssh/desktop_mark.pub user@desktop

Testing the key

After copying the public key, go to Settings → Connections and run an SSH test with the same user@host pair. A successful test confirms the key is trusted.


Remote sync key — manual setup

The sync_backup_to_remote.sh script always uses the key at /root/.ssh/id_ed25519_backup. Generate it once on the backup server:

ssh-keygen -t ed25519 -f /root/.ssh/id_ed25519_backup -N ""
ssh-copy-id -i /root/.ssh/id_ed25519_backup.pub user@backup-host

This key is not managed by the web UI and is not stored in /data/ssh/.


Deleting a key

On the SSH Keys page, click Delete next to any key. Both the private and public key files are removed. If a backup task references that key's host, the backup step will fail until a new key is generated and installed.

Warning

Deleting a key is irreversible. If you delete a key that is in active use, the corresponding backup task will fail at its next run.