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 for Microsoft Windows keep track of changed data blocks in a more efficient way. The driver is intended for servers running applications with large database files.
Keep in mind that the Veeam CBT driver is not supported for file-level backup. To learn more, see Backup Types.
To use the Veeam CBT driver, the Veeam Agent computer must meet the following requirements:
- Run a Microsoft Windows Server OS
- Run the Server edition of Veeam Agent for Microsoft Windows
Before installing the Veeam CBT driver on a computer, consider the following prerequisites:
- If your computer runs Microsoft Windows Server 2008 R2 SP1, make sure the update KB3033929 is installed in the OS.
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.
- If your computer runs Microsoft Windows Server 2008 R2 SP2, make sure updates KB4535102 and KB4516065 are installed in the OS. To learn more, see these Microsoft KB articles: KB4535102 and KB4516065.
The updates allow to use the Veeam CBT driver with 4 KB sector hard drives.
Do not install the Veeam CBT driver on a computer running Microsoft Windows Server 2008 R2 SP1, 2012 or 2012 R2 if one or more volumes on this computer are encrypted with Microsoft BitLocker (or other encryption tool), or if you plan to use Microsoft BitLocker to encrypt volumes on this computer. Concurrent operation of Microsoft BitLocker and Veeam CBT driver may result in driver failures and may prevent the OS from starting.
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 for Microsoft Windows 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:
Information about changed data blocks is registered in 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: