background
The CBT ((change block tracing)) feature of vm in VMware products can effectively help vm perform the incremental backup function. The CBT function can identify and track the blocks that have been modified since the last backup. All these modifications will be stored in the log file China to track and record the changes of the blocks. After enabling CBT on vm, our commonly used backup software (such as vDR (vmware Date Recovery, now VDP), veeam, Unitrends, Commvault and other backup software) will use the CBT function to process incremental backups.
Steps
First, before enabling the change CBT (block tracking) function, make sure that there are no snapshots on the virtual machine, otherwise the data returned by QueryChangedDiskAreas APi may be incorrect.
1) Close the virtual machine to enable the CBT function;
2) Edit the vm configuration, advanced-configuration parameters-add line-add "ctkEnabled", set its value to device true, on the contrary, disable it and set it to false;
3) Add a line again, add scsi0:0.ctkEnabled, and set its value to ture