These days you can install Microsoft Azure Backup Server (MABS) v3 on a server running Windows Server 2019 Datacenter (or Windows Server 2016 Datacenter) , which can be a Hyper-V virtual machine (VM), a VMware VM, a physical host, or even an Azure VM, to backup your on-premises or Azure workloads. To be able to perform item-level recovery of VMs (recover files, folders and volumes), one of the requirements is that you install the Hyper-V role and the Hyper-V PowerShell feature as a prerequisite.
When running Hyper-V inside a Hyper-V or VMware VM you will be using nested virtualization. If you want to read more about this feature you can do so over here
During the installation of a new MABS v3 on a VMware VM (ESXi 7.0.2), and after the Hyper-V role was added, the following errors showed up in the Hyper-V event log: Event ID 41, Event ID 15350 and Event ID 15340.
For example, event with ID 41 showed the following error message:
Hypervisor launch failed, Either VMX not present or not enabled in BIOS.
While running the Get-WindowsFeature command on the VM showed that Hyper-V was installed correctly, in the end this was not completely the case like all previous errors showed.
To fix these errors and to get Hyper-V running like it should, I followed the below steps:
First of all, shut down the VM (in my case I used the vCenter Server) and open the Virtual Machine Settings. Then go the Virtual Hardware tab and expand the CPU options.
There you need to check the box Expose hardware assisted virtualization to the guest OS. Click OK to save.
When you still use an older ESXi version, like 6.5, you should also set CPU/MMU Virtualization to Hardware CPU and MMU.
When you now start the VM, those specific Hyper-V related errors should be gone (check with the current boot timestamp) and all necessary Hyper-V services should be running as expected.
To be able to perform item-level recovery for virtual machines (recover files, folders, volumes) with your MABS server, one of the prerequisites is that the Hyper-V role is enabled. When you run your MABS on a VMware VM you should set Expose hardware assisted virtualization to the guest OS on the virtual CPU to make this possible.