Just a heads up, but VMware dropped the public release of the patch to resolve the Change Block Tracking problem in ESXi 6.0. You can apply the patch using VMware Update Manager, or install it manually.
Logically, remember that you can’t just apply the patch and all is well. You need to reset CBT data to “start fresh” because all changed blocks reported prior to the patch are still suspect. Most backup vendors detail how you do this in VMware, but I wanted to share a few tips in this regard.
- Change Block Tracking can easily be disabled/enabled on Powered Off VMs. That’s not an issue.
- You can reset Change Block Tracking information on a VM by disabling CBT on the VM, taking a snapshot of the VM, deleting the snapshot, and then re-enable CBT. This makes for automation of this very easy. Veeam has a PowerCLI script that can do this as an example, although it is clearly a use at your own risk affair.
Finally, don’t forget to enable CBT on your backup jobs and/or VMs when you’re ready if that was disabled as a workaround. You can do this using PowerShell if you’re using Veeam.