Backup owner check failed

When managing backups in a Proxmox environment, maintaining proper ownership of data files is crucial for ensuring smooth operations and preventing interruptions.

One common error encountered by users in such setups can be :

Copied!qmp command ‘backup’ failed - backup connect failed : command error: backup owner check failed
qmp command ‘backup’ failed - backup connect failed : command error: backup owner check failed

This error typically appears when an ownership mismatch occurs on an existing backup file, blocking backup or restore actions.

Fortunately, fixing this issue is straightforward once the cause is understood.

The error “backup owner check failed” points to a discrepancy between the expected and actual owner of the backup files in the Proxmox Backup Server (PBS) datastore.

Essentially, Proxmox verifies ownership of the backup files to ensure that each virtual machine (VM) or container (CT) only has access to its own data. When a mismatch arises, Proxmox flags the backup as unowned or incorrectly owned, triggering this error.

To resolve this, you’ll need to locate the datastore mount point and correct the ownership setting. Start by identifying the correct path to the datastore where your backups are stored. Once located, navigate to the relevant directory for the affected VM or CT.

The owner file can be found in

Copied!/datastore/mountpoint/<vm>/id/owner</vm>
/datastore/mountpoint/<vm/ct>/id/owner

where “mountpoint” represents the datastore mount, “vm/ct” designates either a virtual machine or a container, and stands for the unique identifier of the VM or CT experiencing the error.

Once you’ve accessed the correct directory, open the “owner” file in a text editor. Verify the content of this file to ensure that it aligns with the owner ID of the VM or CT that the backup belongs to. If the ID does not match, modify it to reflect the correct owner. Save your changes and restart the backup process to check if the error is resolved.

By following these steps, Proxmox Backup Server should recognize the correct ownership of the backup files, allowing you to proceed without encountering the “backup owner check failed” error.

This straightforward adjustment ensures that ownership verification passes, restoring access to backup processes and enhancing the reliability of your backup management with PBS.

Take a look at our features, and contact us for more information about your Proxmox backup management and security needs.