Virtual Machine tasks fail with error "No more space for virtual disk".

Products

• VMware vCenter Server
• VMware vSphere ESXi

Issue/Introduction

• A Virtual Machine residing on an NFSv3 datastore fails to power on/ consolidation.
• While the vSphere Client UI indicates that the datastore has sufficient free space, the following error is displayed under VMs Issues and Alarms tab:

There is no more space for virtual disk /vmfs/volumes/#########-#######-####-############/VM_NAME/VM_NAME.vmdk. You might be able to continue this session by freeing disk space on the relevant volume, and clicking Retry. Click Cancel to terminate this session.

• You will observe warnings similar to the following in var/log/vmkernel.log file :
  

  YYYY-MM-DDTHH:MM:SSZ Wa(180) vmkwarning: cpu#:####)WARNING: NFS: ####: <volume_name>: No space on NFS volume.

Environment

• VMware vSphere ESXi

Cause

• This issue occurs when the backend physical storage array has exhausted its physical capacity, even though the logical NFS export presented to ESXi reports available space.
• This typically happens in environments where the storage is thin-provisioned at the array level. The ESXi host attempts to write to the volume, but the storage processor returns an "Out of Space" error at the file system layer because it cannot allocate more physical blocks.

   

Resolution

• Physical space must be reclaimed or added at the storage array level.
• Engage storage vendor to free up space and/or add additional storage on the backend. 

Additional Information

Physical Storage Reclamation and Expansion Workflow: 

• Log into the management interface of storage provider to verify the actual physical utilization of the pool/aggregate.
• Delete unused snapshots, old volumes, or orphaned files on the storage array to free up physical blocks. 
• If no space can be reclaimed, increase the physical capacity of the underlying storage pool or aggregate. 
• Once the storage vendor confirms physical space is available, click Retry in the vSphere error prompt or attempt the VM task again.