PowerFlex: QueryChangedDiskAreas API Returns Incorrect Sectors

Summary: QueryChangedDiskAreas API returns incorrect sectors after extending virtual machine VMDK file with Changed Block Tracking (CBT) enabled in ESXi 8.0u2.

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Symptoms

CBT's QueryChangedDiskAreas may lose some data changed on the disk after disk is hot-extended. It happens on ESXi 8.0u2 and VMC 1.24.1.

 

Cause

There is an issue in the QueryChangedDisk Areas API.

 

Resolution

In order to resolve this issue, update to ESXi 8.0 Update 2b or newer.

Workaround

  1. Reset CBT after disk is hot-extended. Then, the user must take a full backup immediately.
    It does not fix existing backups, but it ensures that the new ones are good. Follow these steps to reset CBT Resetting Changed Block Tracking for VMware vSphere virtual machines (External Link)

  2. Or, the user extends the disk in offline.

 

Additional Information

This is a duplicate article of VMware Article:QueryChangedDiskAreas API returns incorrect sectors after extending virtual machine VMDK file with Changed Block Tracking (CBT) enabled in ESXi 8.0u2 (External Link)

 

Affected Products

VxBlock and Vblock Systems, PowerFlex rack, PowerFlex Appliance, PowerFlex custom node
Article Properties
Article Number: 000223945
Article Type: Solution
Last Modified: 30 Dec 2025
Version:  2
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