Virtualization Resource Requirements

CPU and Virtualization Extensions

CPU vendors have built special instruction sets to improve virtualization performance
- Intel technology for this is called VT-x (Virtualization Technology)
- AMD calls it AMD-V
Second Level Address Translations (SLAT)
- improves the performance of virtual memory when multiple VMs are installed
- Implemented as:
  - Extended Page Table (EPT) for Intel
  - Rapid Virtualization Indexing (RVI) for AMD
virtualization software requires a CPU with virtualization support enabled
- performance of the VMs will be impaired if hardware-assisted virtualization is not available
- cheaper CPU models ship without the feature
- may be disabled in the system firmware

Info

64-bit hypervisor can run 32-bit guest OSs

providing the hypervisor supports them

32-bit hypervisors will not support 64-bit guest OSs

Each guest OS requires sufficient system memory over and above what is required by the host OS/hypervisor
- E.g.,
  - recommended that Windows 10 be installed on a computer with at least 2 GB memory
  - means that the virtualization workstation must have at least 4 GB RAM to run the host and a single Windows 10 guest OS

VM’s “hard disk” is stored as an image file on the host
hypervisors use a dynamically expanding image format that only takes up space on the host as files are added to the guest OS
More space is required if you want to preserve snapshots
- the state of a disk at a particular point in time
- useful if you want to be able to roll back changes you make to the VM during a session

hypervisor will be able to create a virtual network environment through which all the VMs can communicate and a network shared by the host and by VMs on the same host and on other hosts
Enterprise virtual platforms allow the configuration of virtual switches and routers