---
title: Enable or disable Change Block Tracking on VMware backup
description: "## Using Change Block Tracking on VMware Nuabee backups ### Context of use VMware's Change Block Tracking (CBT) is a VMware ESXi virtual machine backup option which, when activated, enables incremental and differential backups of VMware virtual machines. With each…"
url: "https://nuabee.com/documents/activation-desactivation-changement-block-tracking-on-vmware-backup/"
updated: "2024-09-01"
category: Linux and Windows backup
---

# Enable or disable Change Block Tracking on VMware backup

## Using Change Block Tracking on VMware Nuabee backups

### Context of use

VMware's Change Block Tracking (CBT) is a VMware ESXi virtual machine backup option which, when activated, enables incremental and differential backups of VMware virtual machines.

With each backup procedure, it **downloads only those parts of the virtual machine disk that have actually been modified since the last backup**, thus improving backup times and optimizing the required backup space.

### System requirements

Changed Block Tracking requires the following hardware and software:

- Hardware compatibility of vSphere virtual machine version 7 or higher: ESXi
- NFS or iSCSI datastores
- Thick or thin provisioning
- No RAW disk mapping

### Compatibility with other backup solutions using CBT

Each backup solution that uses CBT makes its own snapshot, and based on the CBT tracking IDs of that snapshot, the backup (changes) is made.

In other words, using two backup solutions with CBT on one VM works well:

1. As long as the snapshots do not take place at the same time.
2. As long as one of the 2 backup solutions does not reset the CBT (typically this is an option in Veeam).

## Disable CBT

### Context

 Nuabee Backup may be unable to use the CBT function and consider the backup as a "warning", stating that it was unable to use CBT for one or more machines.  In this case, it may be necessary to disable the CBT function on the machine causing the problem.

### How to proceed from the console

Go to the VMware backup plan to be modified

[![](https://nuabee.fr/wp-content/uploads/2024-08-28_16h59_27.png)](https://nuabee.fr/wp-content/uploads/2024-08-28_16h59_27.png)

 

Click on "Edit", then scroll down to the "Virtual Machines" tab and uncheck the "Use Changed Block Tracking" (CBT) box.

[![](https://nuabee.fr/wp-content/uploads/2024-08-28_17h00_37.png)](https://nuabee.fr/wp-content/uploads/2024-08-28_17h00_37.png)