disable CBT on job or host

[GabesVirtualWorld]

Hi
Other thread about Hyper-V 2019 performance shows we're having issues with 2019 and CBT. Now we want to disable CBT for the VMs and want to be sure about the following:

- Once CBT has been enabled for a VM by VEEAM or other product, CBT file is maintained by Hyper-V.
- When disabling CBT on the backup job, VEEAM will disregard the CBT info, but Hyper-V is still keeping record of the CBT
- When disabling CBT on the Hyper-V host through VEEAM infra settings, VEEAM will disregard the CBT info for VMs on that host, but Hyper-V is still keeping record of the CBT.

In all cases, I can only completely disable CBT by stopping the VM, removing the MRC / RCT files and be sure to never enable CBT again for that VM.

Is that correct?

Extra info: Our issue is Hyper-V writing to the CBT file, regardless of any backup product using the CBT.

Regards
Gabrie

[PetrM]

Hi Gabrie,

All three statements from your post about CBT are correct but it's difficult to say something about MRC and RCT files deletion as it's not something that we actively test. Looks like it would work, at least according to this topic, I'd try it at first on a test VM. Also, I think that you may look for options to disable CBT at the level of hypervisor on Microsoft forums.

Thanks!