No zvol device link - Proxmox VE Error during backup or snapshot

Hint: In the following, the correction of a specific error is considered. Before performing the steps described, please check carefully whether the cause and circumstances of the error correspond to your situation. The Thomas-Krenn.AG accepts no responsibility for any damage or failure due to incorrect use of the assistance.

This article helps with the error messages no zvol device link and dataset does not exist.

Error message

no zvol device link is reported when creating a backup.

dataset does not exist is reported when creating a snapshot.

Backup

ERROR:Backup of VM 107 failed - timeout: no zvol device link for 'vm-107-disk-1' found after 300 sec found.

Snapshots

saving VM state and RAM using storage 'local-zfs'
513.64 KiB in 0s
2.12 GiB in 1s
completed saving the VM state in 2s, saved 3.69 GiB
snapshotting 'drive-sata0' (local-zfs:vm-222-disk-1)
cannot open 'rpool/vm-222-disk-1': dataset does not exist
usage:
	snapshot [-r] [-o property=value] ... <filesystem|volume>@<snap> ...
For the property list, run: zfs set|get
snapshot create failed: starting cleanup
TASK ERROR: zfs error: For the delegated permission list, run: zfs allow|unallow

Error description

The following information describes a system configuration in which the above-mentioned errors occurred. Furthermore, the cause and potential development of the error message are reported.

Initial situation

Server: Singlenode with Proxmox VE 8.0
Storage: local-zfs with the name rpool
ZFS-Status: OK
error pattern: Snapshots and Backups of the VMs are not possible anymore

Development

The following configuration steps have led to error messages:

Customer deletes local-zfs in Datacenter -> Storage
- deletes the reference within the Web-UI.
- As a result, new VMs cannot be created.
- Previous VMs are not affected.
The customer creates the reference, no error appears
VMs can be restarted without problems
It is uncertain whether restarting the server will cause problems.
Nevertheless, no backups and no snapshots are possible (see error above).

Cause

When adding local-zfs,the ZFS dataset must be selected with the entry rpool/data.

Instead, the pool rpool was incorrectly selected.

Since local-zfs now points to rpool and not to rpool/data, snapshots and backups no longer work.

Solution

Remove local-zfs from Datacenter -> Storage and add it again with the correct path /rpool/data.

Translator: Alina Ranzinger

Alina has been working at Thomas-Krenn.AG since 2024. After her training as multilingual business assistant, she got her job as assistant of the Product Management and is responsible for the translation of texts and for the organisation of the department.

Author: Jonas Sterr

Jonas Sterr has been working for Thomas-Krenn for several years. Originally employed as a trainee in technical support and then in hosting (formerly Filoo), Mr. Sterr now mainly deals with the topics of storage (SDS / Huawei / Netapp), virtualization (VMware, Proxmox, HyperV) and network (switches, firewalls) in product management at Thomas-Krenn.AG in Freyung.