Critical Backup Failure: Error Reading from Source File '/Home/Agents/#-TestDataset/Vddk-Fuse/VMDKname.Vmdk'

Issue

When attempting to backup a virtual machine with the agentless backup solution, you receive the error:

Critical backup failure: Error reading from source file '/home/agents/#-TestDataset/vddk-fuse/VMDKname.vmdk'. Expected bytes (value), actual bytes 0.

Environment

  • Datto SIRIS
  • Agentless Backups

Cause

  • Snapshots on the hypervisor require consolidation.
  • Changed Block Tracking (CBT) requires resetting.
  • The Datto appliance is full.
  • The live dataset on the Datto appliance is corrupt or unusable.

Resolution

Attempt a backup after following each step:

  • Consolidate snapshots on the on the host for the protected machine. Information on this can be found here (external link).

  • Ensure that the Datto appliance has adequate free space for a snapshot.

  • On the Datto appliance, delete the live dataset for the agent.

  • Verify that you can successfully take a manual quiescing snapshot, then Reset the Changed Block Tracking on VMWare (external link).