Unable to download vmdk files for a Powered ON virtual machine

Products

• VMware vCenter Server
• VMware vSphere ESXi

Issue/Introduction

• Downloading vmdk of a Powered ON virtual machine fails with error "Failed to download "[datastore_name] VM_NAME/VM_NAME-flat.vmdk": java.io.IOException: Server returned HTTP response code: 500 for URL: http://localhost:1080/external-vecs/http1/vcsa-fqdn/443/folder/VM-NAME/VM-NAME-flat.vmdk?dcPath=cloud&dsName=ds-name&enc=std"
• When we go to the Download location and extract the zip file, the file size shows only 1KB, and Error report.log displays the above error.
• When attempted to download by navigating to "vSAN datastore > Select VM folder > Select the .vmdk file > Click Downloads: we may see below errors:

Environment

vSphere (All versions)

ESXi (All versions)

Cause

The VMDK files are locked by the ESXi hosts when the virtual machine is powered on. This is expected behavior.

Resolution

• Consolidate Snapshots: Check for and delete any existing snapshots to ensure all data is committed to the base disks.
• Power Off the VM: Gracefully shut down the guest operating system and power off the virtual machine.
• Retry Download: Once the VM is powered off, proceed with the download from the vSAN datastore.