Snapshot consolidation does not complete with "Failed to get copy progress" error

Products

• VMware vSphere ESXi
• VMware vSphere ESXi 8.0

Issue/Introduction

• From the vSphere Client, you may see that the Snapshot Consolidation task fails with error: Failed to get copy progress while consolidating disks from '/vmfs/volumes/<volume UUID>/<vm name>/<snapshot.vmdk> to '/vmfs/volumes/<volume UUID>/<vm name>/<parent disk.vmdk>':

 

• In the virtual machine's vmware.log (/vmfs/volumes/XXXXXXXX-XXXXXXX/VmName/vmware.log) shows the snapshot consolidation progress remains at 0 for several hours and finally times out:
  
  In(05) vmx - SnapshotESXCombineProgressTotal: Snapshot consolidation progress: 0
In(05) vmx - SnapshotESXCombineProgressTotal: Snapshot consolidation progress: 0
......
In(05) vmx - SnapshotESXCombineProgressTotal: Snapshot consolidation progress: 0
Wa(03) vmx - Mirror: scsi0:1: Failed to copy disk: Timeout
  
  
  
• You may also see datastore latency messages indicating high datastore latency, such as these: 

2026-01-28T22:22:10.653Z Wa(180) vmkwarning: cpu0:2098195)WARNING: NFS: 5965: NFS volume MyDatatstore performance has deteriorated. I/O latency increased from average value of 677852(us) to 1457503(us). Exceeded threshold 10000(us).

• On the ESXi host, the /var/run/log/vmkernel.log you see issues with:
  
  

• • I/O being aborted  (VMFS) 

Fil6: 4094: '<datastore name>': Fil6 file IO (<FD c32 r57>) : IO was aborted

 

• • or the connection timing out during consolidation on NFS datastores:
    
    

2026-01-28T22:24:29.298Z In(182) vmkernel: cpu38:2358285)NFS: 7038: Status:No connection. Retrying synchronous write I/O 1 of 25 times

 

• • Additionally, with NFS datastores, you may also see RPC socket space filling:
    
    

2026-01-28T22:23:10.981Z In(182) vmkernel: cpu0:2358785)SunRPC: 5704: Socket space full. rpc queued. 0x29d1be11

Environment

• VMware ESXi 8.0

Cause

• IO is being aborted or connections are being dropped due to an issue on the underlying SAN or related network/fabric connectivity which is preventing snapshot consolidation from proceeding.

Resolution

• Please engage Storage and/or Network teams/vendors to investigate latency and/or connectivity issues.