Changed Block Tracking for VMware Backups
Changed Block Tracking (CBT) is a VMware feature that optimizes backup procedures to back up only changed blocks during incremental backup plan runs.
Enable Changed Block Tracking in Backup Plans
Changed Block Tracking feature can be enabled for any virtual machine backup plan. To learn how to enable it, refer to the VMware and Hyper-V Backup chapter.
Changed Block Tracking Explained
Changed Block Tracking identifies the disk sectors modified between two changeset stamps.
On VMFS partitions, CBT can also identify all the disk sectors that are in use.
Changed blocks of virtual disk are tracked on the virtualization layer. During incremental runs the backup plan only process blocks that have been changed since the last backup and blocks in use.
For more information about the feature refer to VMware documentation