Unable to back up files on a storage space direct csvfs volume with Microsoft Azure Backup.

Hi Lucas Denotter

https://learn.microsoft.com/en-us/windows-server/failover-clustering/failover-cluster-csvs#backing-up-csvs
Volume-level backups can be executed from any node within the cluster that has access to the CSV. Please ensure that the node you initiate the backup from is actively connected to the CSV to avoid any access issues.

If your backup application supports it, I strongly recommend using application-consistent snapshots. This method ensures that your data is captured in a consistent state, reducing the risk of data corruption—especially important for virtual machines and applications running on CSVs.

If you're using Windows Server Backup, please note that it only supports crash-consistent backups for CSVs. While this may be sufficient for some scenarios, it may not meet the backup requirements for critical applications or VMs, as it does not guarantee data consistency.

CSVs are optimized for high availability in clustered environments. As such, traditional file sharing (e.g., using SMB shares) is generally not supported on CSVs, which may explain any issues you're encountering when trying to share folders within a CSV.

https://learn.microsoft.com/en-us/azure/backup/backup-azure-mabs-troubleshoot#common-issues

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Hi Lucas Denotter

I just wanted to check if the above provided information worked for you or if you need any further assistance?

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Hello Lucas Denotter,

I would like to check if the issue has been resolved or if you need any assistance. Please feel free to let us know, as we are always here to help.

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Hi Lucas Denotter,

I see that Vinod Pittala and others have already highlighted key limitations around folder-level visibility on CSV volumes and the importance of application-consistent backups from the active node.

Building on that, one next approach you could try is ensuring that the Microsoft Azure Backup agent is running on the cluster node that currently owns the CSV. Even though all nodes in the cluster can access the CSV, certain backup operations need to be triggered from the active owner node for reliable results.

check the current CSV owner by running

Get-ClusterSharedVolume | Select-Object Name, OwnerNode

Once confirmed, try the steps below

• Open the Azure Backup agent directly on that node
• Try backing up using the Volume-level selection (rather than attempting to browse folders inside C:\ClusterStorage)
• Make sure you're not using a redirected CSV path or non-owner node, as this can cause blank folders or snapshot failures during recovery

If you're still hitting issues even with these adjustments, consider testing with Azure Backup Server (MABS), which has deeper support for clustered scenarios like Storage Spaces Direct.

Please let us know if it was helpful, and feel free to reach out if you have any further queries.