Veeam Backup issue: Proxmox VM backup failing

[Chetna]

We are experiencing an issue with backup failures for a Proxmox Virtual Environment VM (VM ID: 105). The backups are being triggered via Veeam, but the failure appears to originate from the Proxmox layer.

Below are the relevant log excerpts observed during the failure:

ERROR: Backup of VM 105 failed – interrupted by signal
unable to connect to VM 105 QMP socket – timeout after 51 retries
TASK ERROR: can't lock file '/var/lock/qemu-server/lock-105.conf' – got timeout

Based on initial analysis and feedback from Veeam support, Proxmox is unable to connect to the QMP socket for the VM and is also unable to obtain a lock on the VM configuration file.

Actions already performed:
Verified VM status and running processes
Attempted VM restart and retried backup

Can you please assist with further troubleshooting.

 

[bbgeek17]

Hi @Chetna , welcome to the forum.

The log snippet you posted is not nearly enough to suggest a meaningful troubleshooting direction. We do not know where the log originated, what associated task was running on PVE at the time, what initiated the task, or under what conditions it occurred.

For more targeted debugging, you will need to collect time-correlated logs from both Veeam and PVE. From your description, it sounds like you already engaged Veeam through your support entitlement and were redirected toward PVE support. That is one of the common challenges when integrating two products that do not have a formal joint support agreement.

Your best approach is to meticulously gather all diagnostic information that Veeam can provide and submit it through a support ticket with Proxmox GmbH.

One additional troubleshooting step you can try: deploy a freely available instance of PBS, even temporarily as a VM, and attempt to back up the affected VM through PBS instead.

• If the same issue occurs, you have effectively excluded an external black-box application from the equation, which significantly narrows the troubleshooting scope.
• If the PBS backup succeeds, that would strongly suggest the issue lies in how Veeam integrates with PVE.

Hope that helps.

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