PVC expansion fails for vSAN File Share with error: "volume expansion is only supported for block volume type"
Article ID: 438354
Updated On:
Products
Issue/Introduction
- Attempts to resize or extend a file-based Persistent Volume Claim (PVC) in a vSphere Kubernetes Service (VKS) or Tanzu Kubernetes Grid (TKG) cluster, the operation fails.
- The requested storage increase does not reflect in the volume, and the PVC remains at its original capacity.
- The following error is observed while describing the affected PVC:
kubectl describe pvc <pvc-###################>
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal ExternalExpanding 18s volume_expand waiting for an external controller to expand this PVC
Normal Resizing 2s (x6 over 18s) external-resizer csi.vsphere.vmware.com External resizer is resizing volume pvc-###################
Warning VolumeResizeFailed 2s (x6 over 18s) external-resizer csi.vsphere.vmware.com resize volume "pvc-###################" by resizer "csi.vsphere.vmware.com" failed: rpc error: code = Unimplemented desc = volume expansion is only supported for block volume type
Cause
"File volumes do not work in conjunction with functionalities such as extend volume and encryption." — Provisioning File Volumes with vSphere Container Storage Plug-in
This is a current architectural limitation of the vSphere CSI driver. While the driver supports volume expansion for block-based volumes (VMDKs), expansion for file-based volumes (RWX shares) provisioned via vSAN File Services is not supported. Consequently, changes to the storage request for NFS-backed PVCs are not processed by the driver.
Resolution
As this is a known product limitation, the only available workaround is to perform a file-level migration by backing up and restoring the PVC using Velero with File System Backup (FSB).
Feedback
