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HyperV2012 CBT Backups NBU vs BEXEC

Level 0

Its my understanding that Backup Exec supports CBT backups of HyperV 2012 - but NetBackup does not. Is this correct? If so why - NBU has features that I really want but something as simple as lacof k CBT for HyperV 2012 would kill this option for me.....

Can anyone comment?


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To my understanding native CBT was added in Windows server 2016. For Hyper-2012 you have to use VSS based backups.

Some other vendors has made their own CBT implementation for Windows 2012 - but strictly speaking that means it's a unsupported backup methods.

Can you refer to a link that state that Backup Exec uses CBT for windows 2012 ? Then the community can have a look at it.

Level 6
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I found a Technical WhitePaper  that says the following on p.10: 

Backup Exec 2014 supports changed block tracking (CBT) for Hyper-V environments. This means that Backup Exec can track the changes that have occurred against a virtual machine since the last backup operation at the block level, and capture only the block-level changes since the last backup (incremental) or since the last full backup (differential).

I cannot answer the question as to why NBU does not offer the same functionality for Hyper-V 2012.

All I know is that NBU8 and later offers WMI support for W2016 with BLIB (Block-level Incremental Backups).

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I think "supports" is a bit incorrect wording. Change Block Tracking in a proper sense, like it is used in VMware appeared in Hyper-V 2016 as the RCT feature, full stop. Now when issues with Hyper-V 2012 backups became apparent but support for a proper CBT was not available, every man and his dog come up with "proprietory driver" to make those "CBT"-type backups which are more-or-less depending on the vendor were poor man snapshot dedupe features. Why it so? Because the only way Windows 2012 with Hyper-V role can give you a backup is through the VSS framework which could only make a VSS-consistent snap of a VHD/VHDX.The other really ugly method called "Microsoft Incremental Backup" which requires to run VHDX all the time with a snapshot attached which is consolidated during every "incremental" backup.

Long story short, with no proper support from the hypervisor, incremental backups of Hyper-V are good from Hyper-V 2016 onwards, in 2012 any solution is a bit of a kludge and may have issues, BUE included