Ensure that a VNF-C uses the most up-to-date virtual machine hardware version. The virtual machine hardware version reflects the supported virtual hardware features of the VM. These features correspond to the physical hardware that is available on the ESXi host where the VM runs.
Virtual hardware features include the BIOS and Extensible Firmware Interface (EFI), the available virtual PCI slots, the maximum number of CPUs, the maximum configurable memory, and other typical hardware characteristics.
Different VM hardware versions support different components and different amounts of resources, so you must use uniform VM hardware versions for all VMs comprising a VNF. For example, the VM hardware version 14 supports a maximum of 6128 GB of RAM for a VM, whereas the VM hardware version 11 supports up to 4080 GB of RAM.
VM hardware versions also enable processor features, so the best practice is to use the latest virtual hardware version to expose the new instruction sets to the VM. Avoid mismatches between VNF-Cs configured with different VM hardware versions because it impacts the performance.
The differences in the virtual hardware versions are listed in Hardware features available with virtual machine compatibility settings (2051652).
The latest VM virtual hardware versions and their matching hypervisor versions are listed in Virtual machine hardware versions (1003746).
For information about upgrading a virtual hardware version, see Upgrading a virtual machine to the latest hardware version (multiple versions) (1010675).
Summary of Recommendations:
Use the latest virtual machine hardware version.
Use a uniform virtual machine hardware version across all the VMs that comprise a VNF.