Backup time for HyperAgent increases

Summary

Incorrect CBT (Changed Block Tracking) information on ESXi host leads to the incorrect recognition of the the actual used area. This causes an increase in the backup source area and subsequently extends the backup process time.

In the backup task log, if CBT information is incorrect, the size of the used blocks is reported as larger than the actual used area. Typically, the size of Used blocks is reported as the same as the virtual hard disk size.

09/12/2022 04:07:11.214 Used blocks: 234737798 [15383776329728 bytes (14.0 TB)]

This issue of the incorrect recognition of the actual used area may arise with Thin provisioning virtual HDD.

Workaround

Please follow these steps to reset the Changed Block Tracking (CBT) for the virtual machine:

Reference
https://kb.vmware.com/s/article/1020128

1) Shut down the virtual machine.

2) Delete any existing snapshots entirely.

3) 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.

For your information, please access the following site and check the information of the related issue recognized on ESXi 8.0 U2.
https://kb.vmware.com/s/article/95965

Target Product

- ActiveImage Protector 2018 / 2022 HyperAgent

(13451232377113)