CBT reset on VM after cross vCenter vMotion

[Theta12]

I'm fairly sure I already know the answer to this question, but am asking anyways to be sure.  We have a production site and DR site both with vCenter 6.7 u2 appliances, hosts running 6.5 u3, Nimble San on the back ends and Veeam for backup.  I've configured enhanced link mode with both vCenters in the same SSO domain.  Cross vcenter vmotion works as expected and I'm able to migrate a VM to the DR site and back again with no issues.  However, I noticed that whenever I move the machine back, Veeam must now take a completely new Full backup because (I'm assuming) all the CBT markers have been reset from the migration.  Veeam already says it depends on Vmware's CBT to know which blocks to back up, so is there a way to retain CBT during these vMotion events?  I have both vCenter appliances registered in my Veeam backup and recovery console.

[nachogonzalez]

It makes sense to me:

Veeam knows how to find the CBT markers in vCenter A, if you migrate the VM to the other vCenters those CBT markers wont be on available to the same vCenter.

[Theta12]

Yes but I moved the same VM BACK to the original vCenter well before the nightly backups kicked off.  The VM lived in vCenter B for roughly 30 minutes before being moved back to it's original location (same host and datastore).

[nachogonzalez · Accepted solution]

Yes, but on a cross vCenter vMotion  when you migrate a VM from vCenter A to vCenter B you move VM files and disks form storage, in order to do so a consolidation is needed.
When you move it back to vCenter A files might or might not be on the same locations so CBT markers might not be accurate, so they are recrated

[Theta12]

This was my assumption as well and was what I was trying to confirm.  I'll go ahead and mark your answer correct as i had thought the same thing and no one else has chimed in.

[nachogonzalez]

Nice, Hope it worked