Veeam produces an error such as this
Verifying changed block tracking... Disk "Hard disk 'no'" has incorrect changed block tracking configuration. Backing up object "[VMFS'no' myserver.com/myserver.com.vmdk" One or more VM disks have incorrect changed block tracking configuration. To resolve this, open VMware vSphere Client, right-click the VM, choose Edit Settings, Options tab, select General, click Configuration Parameters, and set all entries with ‘ctkEnabled’ substring to false. Veeam Backup will then automatically re-enable changed block tracking with the correct settings during the next job run. BackupDiskFull failed Client error: Failed to open VDDK disk [[VMFS'no' myserver.com/myserver.com.vmdk ( is read-only mode - [true ) Failed to open VMDK. Logon attempt with parameters [VC/ESX: [vcenter;Port: 443;Login: [admin;VMX Spec: [moref=vm-100135;Snapshot mor: [snapshot-100137;Transports: [san failed because of the following errors: Failed to open VMDK. Logon attempt with parameters [VC/ESX: [vcenter01;Port: 443;Login: [admin;VMX Spec: [moref=vm-100135;Snapshot mor: [snapshot-100137;Transports: [nbd failed because of the following errors: Server error: End of file
Sometimes this issue will resolve itself after the next backup attempt. Otherwise, to fix, the following settings needed to be changed:
- Go to the server in vcenter
- Turn off the server
- Go to ‘Edit Settings’
- Highlight ‘Harddisk’
- In the ‘Mode’ Parameter, make sure that the ‘Independent’ checkbox is off if it does not then turn it off.
- Restart the server and try to restart job in veeam backup.
Hopefully, this will work, but if it doesn’t work or it is already set to these settings then follow these steps afterwards,
- The following steps will reset CBT (Changed Block Tracking) on the guest VM:
# Gracefully shutdown the VM
# Right-click the VM, click “Edit settings”, find the “Options” tab and click “Configuration Parameters”
# Set the “ctkEnabled” value to false
# Set the “scsi0:x.ctkEnabled” value to false for each disk of the VM in question
# Open the source folder and remove any -CTK.VMDK files.
# Power on the VM
# Power off the VM again. This step is needed to update the CTK table.
# Power on the VM