Veeam Changed Block Tracking Driver
You can set up Veeam Agent for Microsoft Windows to use the Veeam CBT driver instead of the default CBT mechanism. The Veeam CBT driver is a class filter driver for volume devices that helps Veeam Agent keep track of changed data blocks in a more efficient way. The driver is intended for computers running applications with large database files. The Veeam CBT driver is supported for volume-level and file-level backups.
In case of the file-level backup, consider the following:
To use the Veeam CBT driver, the Veeam Agent computer must meet the following requirements:
- Run a 64-bit version of Microsoft Windows OS.
- Run one of the following OSes:
- Microsoft Windows 11 (versions 21H2, 22H2).
- Microsoft Windows 10 (from version 1803 to version 22H2).
- Microsoft Windows Server OS that is supported by Veeam Agent. For more information, see System Requirements.
- Run the Workstation or Server edition of Veeam Agent for Microsoft Windows.
Consider the following:
The update adds the SHA-2 code signing support that is required for verification of the Veeam CBT driver signature. Without this update installed, the OS running on a protected computer will fail to boot after you install the Veeam CBT driver. To learn more, see this Microsoft KB article.
To enable the advanced CBT mechanism provided by the Veeam CBT driver, you need to install the driver in the Veeam Agent control panel. You can perform this operation at any time you need. To activate the driver after installation, Veeam Agent needs to reboot the computer. After computer reboot, the Veeam CBT driver will start keeping track of changed data blocks on computer volumes whose data you have selected for backup in the Veeam Agent backup job settings.
In contrast to the default CBT mechanism that supports NTFS volumes only, the Veeam CBT driver can keep track of changed data blocks on volumes that use the following file systems:
- FAT (only for volume-level backups)
Information about changed data blocks is registered in special VCT files. VCT files are stored in the C:\ProgramData\Veeam\EndpointData\CtStore folder on the Veeam Agent computer. When the backup job runs, Veeam Agent for Microsoft Windows uses VCT files to find out what data blocks have changed since the last run of the job, and copies only changed data blocks from the backed-up volume.
If you use the Veeam CBT driver, the C:\ProgramData\Veeam\EndpointData\CtStore folder accessibility is crucial for a successful backup. Consider the following:
- The folder and its content must not be compressed or encrypted.
- The folder and its parent folders must not be reparse points.
Consider the following: