Question About CSI Driver Compatibility and Backup Target in Harvester

Hi Harvester Community,

I am currently using Harvester with a custom CSI driver to manage volumes for my VMs. My CSI driver allows me to create snapshots of individual volumes, but I am particularly interested in leveraging Harvester’s backup target feature to perform VM-level backups (which include VM metadata, configuration, and all associated volumes).

I understand that Harvester uses Longhorn as the default storage engine, and it attempts to manage snapshots and backups via Longhorn when using the backup target feature. However, since I’m using my custom CSI driver for VM volumes, I’m unsure about:

  1. Compatibility:
  • Does the Harvester backup target feature work when the VM volumes are managed by a custom CSI driver instead of Longhorn?
  • Can Longhorn treat my CSI-managed volumes as raw data during the VM backup process?
  1. Restoration Process:
  • If backups can be performed successfully, does the restoration process support reattaching custom CSI-managed volumes to the restored VM?

I’ve also noticed some unexpected behavior where Longhorn tries to build a mount path for the volumes, and I am not able to specify mount options when creating nfs backup target.

For additional context, I’ve raised a GitHub issue describing my setup and concerns:
Harvester Issue #7019

I’d appreciate any guidance or shared experiences from the community regarding the compatibility of custom CSI drivers with Harvester’s backup and restoration workflows.

Thank you for your time and support!

Best regards,
Julien