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So if you use vSphere ESXi 6.0 and a backup solution that is relying on CBT (changed block tracking) you should take care of this KB article, as your virtual machine backup might be inconsistent. And maybe you know it for sure when you need your backup most.
Here is what VMware writes about the issue:
This issue occurs due to an issue with CBT in the disklib area, this causes the change tracking information of I/Os that occur during snapshot consolidation to be lost. The main backup payload data is never lost and it is always written to the backend device. However, the corresponding change tracking information entries which occur during the consolidation task are missed. Subsequent QueryDiskChangedAreas() calls do not include these missed blocks, hence a backup based on this CBT data is inconsistent.
At the moment there is no real resolution for the issue.
VMware offers three workarounds – but i guess none of them will make you happy:
downgrade your ESXi hosts to 5.5 and the virtual hardware from 11 to 10
do full virtual machine backups instead of incremental backups
shutdown the virtual machines before doing an incremental backup
Backing up a Changed Block Tracking enabled virtual machine in ESXi 6.0.x returns incorrect changed sectors (2136854)
http://www.running-system.com/attention ... -esxi-6-0/
