Change Block Tracking (CBT) for Hyper-V

Question

I wanted to know if there are any recommendations when using CBT with third-party backup software, how often once needs to take a Full VM Backup. If the CBT keeps track of changes made since the last full, can it handle a once-per-year Full? Are there any storage/size limitations?

Answer 1

Hi Reuvy,
Based on my research there‘s no written storage/size limitations.
For deep investigation and better solution I would suggest that you try a Microsoft Support ticket. If the issue has been proved as system flaw, the consulting fee would be refund. You may find phone number for your region accordingly from the link below.
Global Customer Service phone numbers:
https://support.microsoft.com/en-us/help/13948/global-customer-service-phone-numbers

Thanks for your understanding.
Best Regards,
Danny

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Answer 2

Hi Reuvy，
I did some research but somehow it seems that there’s not many official documents over this topic. Maybe you can take a look at this：
https://bp.veeam.com/vbr/VBP/Support/S_Hyper-V/interaction.html
Please note: Information posted in the given link is hosted by a third party. Microsoft does not guarantee the accuracy and effectiveness of information.

Thanks for your understanding.
Best Regards,
Danny

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Answer 3

Sorry, but that is referring to a different topic altogether.

Answer 4

I have contacted the vendor. They claim (I think rightfully so) that CBT is Microsoft's technology/API, and they are just using the option. Behind the scenes windows is doing all the work. The OS is the one who is maintaining the changed blocks listing, and when they call the OS, it tells them which blocks have been modified.

Answer 5

Hi Reuvy,
Ok. Please take a look at this article：
https://learn.microsoft.com/en-us/system-center/dpm/back-up-hyper-v-virtual-machines?view=sc-dpm-2019

Personally，since I have no idea about what tool you want to use, maybe you can find the backup method from this article, and set the frequency as you want. My suggestion is that if possible，backup the VM at least once a season in case of unexpected error.

Thanks for your understanding,
Best regards,
Danny

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