It is important to 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.
You must use uniform VM hardware versions for all VMs comprising a VNF. This is especially important because different VM hardware versions support different components and different amounts of resources. For example, VM hardware version 14 supports a maximum of 6128 GB of RAM for a VM, whereas VM hardware version 11 supports 4080 GB of RAM. VM hardware versions also enable processor features, which is why the best practice is to use the latest virtual hardware version to expose new instruction sets to the VM. Mismatches between VNF-Cs configured with different VM hardware versions impact the performance and must be avoided.
- 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).
- Upgrading the virtual hardware version is described in Upgrading a virtual machine to the latest hardware version (multiple versions) (1010675).
Recommendations
- Use the latest virtual machine hardware version.
- Use matching virtual machine hardware and ESXi versions.
- Use uniform virtual machine hardware version across all the VMs that comprise a VNF.
