Storage vMotion fails with error: "Failed to copy source (vmname.vmdk) to destination (<destination path>/vmname.vmdk): Address temporarily unmapped. Failed to copy one or more disks"

Products

• VMware vSphere ESXi

Issue/Introduction

• Storage vMotion fails with an "address temporarily unmapped" error:
  
   A fatal internal error occurred. See the virtual machine's log for more details. 2025-06-16T20:16:17.238553Z Failed to copy source (/vmfs/volumes/UUID/vmname/vmname.vmdk) to destination (/vmfs/volumes/UUID/vmname/vmname.vmdk): Address temporarily unmapped. Failed to copy one or more disks.
 
 Error stack:
 Failed to copy source (/vmfs/volumes/UUID/vmname/vmname.vmdk) to destination (/vmfs/volumes/UUID/vmname/vmname.vmdk): Address temporarily unmapped.
 Failed to copy one or more disks.
 A fatal internal error occurred. See the virtual machine's log for more details.
• The vmware.log for the VM and the vmkernel.log for the host also show similar "Address temporarily unmapped" errors.
• The vobd.log has errors like An attached device eui.####################:1 may be offline. The file system [datastore_name, UUID] is now in a degraded state. While the datastore is still available, parts of data that reside on the extent that went offline might be inaccessible. for the same storage location.

Environment

ESXi (all versions)

Cause

The Storage vMotion failure with the error Address temporarily unmapped typically indicates that the ESXi host is attempting to access a data block on a storage device that is currently offline, inaccessible, or misconfigured. This often occurs on multi-extent VMFS datastores where one of the backing LUNs has lost connectivity.

Potential Causes

• Offline Storage Extent: If the VM resides on a datastore spanned across multiple LUNs, one of those extents may be offline or administratively detached.
• Missing Storage Rescan: If the datastore was recently expanded or extended, the ESXi host may not have updated its internal mapping, leading to a mismatch between the expected and actual disk layout.
• Datastore Corruption: Severe metadata corruption on the VMFS volume can prevent the host from correctly mapping file blocks to the physical disk.

Resolution

1. Validate Datastore Extents: Run the following command on the ESXi host to check if any partitions are marked as offline:

   vmkfstools -Ph -v10 /vmfs/volumes/[DatastoreName]

   Review the output for messages such as (device ... might be offline) or (One or more partitions spanned by this volume may be offline).

2. Check for Device Connectivity: Verify that all underlying devices are visible to the host:

   esxcli storage core device list -d [Device_ID]

3. Perform a Cluster-Wide Rescan: Ensure that all hosts in the cluster have an updated view of the storage:

   • Navigate to the Cluster > Configure > Storage > Storage Adapters.
   • Click Rescan Storage and ensure both Scan for new Storage Devices and Scan for new VMFS Volumes are selected.