VMware ESXi 8.0 Update 2b is out and contains a lot of bug fixes. One of the fixes I want to mention is a bug in CBT:
Changed Block Tracking (CBT) might not work as expected on a hot extended virtual disk:
In vSphere 8.0 Update 2, to optimize the open and close process of virtual disks during hot extension, the disk remains open during hot extend operations. Due to this change, incremental backup of virtual disks with CBT enabled might be incomplete, because the CBT in-memory bitmap does not resize, and CBT cannot record the changes to the extended disk block. As a result, when you try to restore a VM from an incremental backup of virtual disks with CBT, the VM might fail to start.
As a workaround, there were two options: not to use hot extend and perform disk extend operations when the VM is powered off, or create periodically full backups to reset the CBT.
So, if you’re running ESXi version 8.0 Update 2, you should consider updating to the 8.0 Update 2b as soon as possible.
You can read about other release notes here.
