I was reading the release notes of the 9.5 version and noticed the following Known Issues with Hyper-V :
Resilient Change Tracking (RCT) returns incorrect changes for VMs which had their virtual disks moved with Storage Live Migration, resulting in corrupt backups. This is a Hyper-V 2016 issue that Microsoft is planning to address in the future update. Until then, disable the use of changed block tracking for any jobs processing such VMs.
• Application-aware processing of VMs with guest OS other than Windows Server 2016 fails with the “Failed to take in-guest VSS snapshot COM error: Code: 0x80042308” error. This issue is fixed in the recent Windows Updates for the corresponding operating systems.
• Application-aware processing of Active Directory domain controllers running on guest OS other than Windows Server 2016 fails with the “Failed to create VM recovery checkpoint” error (32770). This is a Hyper-V 2016 issue that Microsoft is planning to address in the future update.
• Backing up VMs from Hyper-V cluster in rolling upgrade is supported, however RCT will not be leveraged until the upgrade is completed for all nodes and cluster functional level is upgraded to Windows Server 2016. Keep in mind that VMs virtual hardware version must be upgraded to version 8.0 before RCT can be leveraged on the VM.
Is there a way to track or find out if and when these bugs will be resolved ?
The Resilient Change Tracking (RCT) was a big move forward for Hyper-V as it provided the baseline for change tracking in Hyper-V VM's instead of relying on the CBT driver provided by the backup provider (VEEAM in this case).
However, this bug is proving that we now will have to rely on the Microsoft QA to ensure no major bugs surface with the RCT, otherwise there is a strong possibility of backup corruption ! Unfortunately this bug proves that it could be a bumpy ride ahead