Incomplete CBT Activation in Incremental VM Backup | Vembu-VMBackup

CBT Not Enabled for Incremental VM Backup in BDRSuite for VMware

KB ID: 105008
Issue:
CBT (Changed Block Tracking) not being enabled can lead to errors during VMware backups. This error message may arise if CBT is disabled after a Full Backup or the preceding incremental backup. Various scenarios can trigger this problem:
1. CBT for the VM might have been manually disabled.
2. Another application accessing the VM's CBT could intentionally disable it for certain operations.
3. An application that accessed the VM's CBT may have attempted to disable it but failed during the re-enabling process.
Solution:
1. Enable CBT for the VM:
   To rectify the issue, follow these steps:
  1. Power off the VM.
  2. Right-click the VM, select "Edit settings," locate the "Options" tab, and click "Configuration Parameters."
  3. Set the value of "ctkEnabled" to "True."
  4. let the value of "scsi0:x.ctkEnabled" to "True" for each disk of the relevant VM.
  5. Remove any -CTK.VMDK files from the source folder.
  6. Power on the VM.
  7. Power off the VM again. This step is crucial for updating the CTK table.
  8. Power on the VM.
  9. Re-run the backup job.
2. Additional Full Backup for Single VM:
If the backup job is configured for a single VM, consider running an extra full backup.
3. Additional Full Backup for Multiple VMs:
If the backup job involves multiple VMs, and all these VMs encounter the same issue, it's advisable to perform an extra full backup.
 Note: If only specific VMs among the multiple VMs in the backup job face the aforementioned issue, it's recommended not to run an additional full backup. Instead, run an incremental backup for those specific VMs.
It's crucial to choose the appropriate solution based on your scenario to ensure a seamless VM backup process.
    • Related Articles

    • Error: CBT Not Enabled for VM

      KB ID: 105007 Problem: When attempting to back up a virtual machine using BDRSuite, users may encounter an error message indicating that Changed Block Tracking (CBT) was not enabled for the VM. This prevents the successful backup of the virtual ...
    • Title: Backup Success with CBT Failure: Handling Full Resend of VM Data in BDRSuite

      KB ID: 105070 Summary: This knowledge base article addresses the scenario where a backup operation is reported as completed successfully, but Change Block Tracking (CBT) fails for a specific VM in BDRSuite. This situation arises due to multiple ...
    • Addressing Backup Challenges: Resolving 'Failed to Perform Pre-backup Steps :: CBT Not Enabled' Error

      KB ID: 23 Issue: "Failed to perform pre-backup steps :: CBT not enabled. Backup cannot continue." This problem is commonly encountered in VMware ESXi 5.5.x machines due to a known issue with enabling Changed Block Tracking (CBT), as explained in the ...
    • VM Not Found Issue during Incremental Job in BDRSuite

      KB ID: 105035 Summary: This knowledge base article addresses the "VM Not Found" error encountered while attempting to execute an incremental backup job within the BDRSuite application. The error arises due to the unavailability or corruption of the ...
    • VMware Backup and Recovery

      Overview BDRSuite offers agentless backup solutions for VMware ESXi & vCenter. This eliminates the need to install backup agents on each VM. It also provides flexible storage, instant & granular recovery, and centralized management for efficient VM ...