Snapshot Creation Fails with "Object type requires hosted I/O" error and Hard Disk Displays 0MB

Products

• VMware vCenter Server
• VMware vSphere ESXi

Issue/Introduction

When attempting to take a snapshot of a virtual machine on an ESXi host, the following symptoms occur:

• The snapshot operation fails with the error: An error occurred while saving the snapshot: Object type requires hosted I/O.
• In the vSphere Client, the capacity of a virtual disk displays as 0MB under VM > Edit Settings.
• A prompt may appear asking to update the value of the Hard Disk.
• The ESXi host's  /var/run/log/hostd.log contains entries similar to:
  DISKLIB-LINK : DiskLinkOpen: Failed to open '/vmfs/volumes/<volume_name>/<vm_name>/<vmname>.vmdk': : Object type requires hosted I/O
DISKLIB-CHAIN : DiskChainOpen: "/vmfs/volumes/<volume_name>/<vm_name>/<vmname>.vmdk": failed to open: Object type requires hosted I/O.

Environment

• vCenter server 8.x
• vSphere ESXi 8.x

Cause

• The virtual disk (VMDK) is utilizing an unsupported hosted sparse format, specifically the twoGbMaxExtentSparse create type.
• ESXi does not support snapshot operations on hosted formats typically produced by VMware Workstation, Fusion, or third-party conversion tools.
• The 0MB display is a side effect of the ESXi management agents (hostd) being unable to correctly parse the descriptor of an unsupported disk type during the snapshot request.

Resolution

1. Power off the affected virtual machine.
2. Log in to the ESXi host command line interface via SSH as root.
3. Navigate to the directory containing the virtual machine files: cd /vmfs/volumes/<DATASTORE_NAME>/<VM_NAME>/
4. Verify the disk type by checking the descriptor file to confirm it outputs createType="twoGbMaxExtentSparse"
   cat <VM_NAME>.vmdk | grep createType


5. Clone and convert the virtual disk to a native ESXi thin-provisioned format:
   vmkfstools -i "OriginalDisk.vmdk" "ConvertedDisk.vmdk" -d thin
   
   
6. In the vSphere Client, open the Edit Settings menu for the virtual machine.
7. Remove the original Hard Disk. Do not select "Delete files from datastore".
8. Add a New Device and select Existing Hard Disk.
9. Select the newly created ConvertedDisk.vmdk.
10. Power on the virtual machine and verify the disk capacity displays correctly and snapshot operations proceed without the hosted I/O error.

Additional Information

Types of supported Virtual Disks on ESXi hosts

Cloning and converting virtual machine disks with vmkfstools