Because of the wrong information of CBT (Changed Block Tracking) on ESXi host, the entire area of virtual hard disk is falsely recognized as used. As a result, the backup source area increases and the backup process time increase.
If the information of CBT is wrong, the used blocks size is the same as virtual hard disk size in backup task log.
* Usually, the used area is detected as Used blocks, the used area is smaller than the size of virtual hard disk.
09/12/2022 04:07:11.214 Used blocks: 234737798 [15383776329728 bytes (14.0 TB)]
You may get this problem, when running HyperBack (agentless backup task).
Since agent-based backup requiring installation of ActiveImage Protector does not use CBT information of virtual machine, you do not get this problem.
Please use the following operating procedures and clear CBT of virtual machine.
1) Shut down the virtual machine.
2) Please entirely delete the snapshot, if any.
3) Please edit the settings for the virtual machine and disable CBT.
ctkEnabled : FALSE scsi0:0.ctkEnabled : FALSE *When connecting multiple virtual disks, set the value to FALSE according to the number of disks.
4) Boot up the virtual machine.
5) Please make sure that "xxx-ctk.vmdk" does not exist in the datastore of the virtual machine.
6) Shut down the virtual machine.
7) Edit the settings for the virtual machine and enable CBT.
ctkEnabled : TRUE
scsi0:0.ctkEnabled : TRUE
8) Boot up the virtual machine.
9) Please make sure "xxx-ctk.vmdk" file is created in the datastore of the virtual machine.
10) Run HyperBack and check the behavior.
- ActiveImage Protector 2018 / 2022 HyperAgent