CHAPTER 1.3 Flashcards
(23 cards)
Before Virtualization
- Runs single OS per machine at a time
- Software is dependent on hardware
- May have conflicts when multiple applications run
on the same machine - Underutilizes resources
- Is inflexible and expensive
After Virtualization
- Runs multiple OS per physical machine
concurrently - Makes OS and applications hardware independent
- Isolates VM from each other, thus no conflict
- Improves resource utilization
- Offers flexible infrastructure at low cost
Server Virtualization
Virtualization refers to the creation of a virtual resource such
as a server, desktop, operating system, file, storage or
network.
Server Virtualization
The hypervisor layer runs directly on the system hardware.
Server Virtualization
Allows multiple OS to run on a physical server simultaneously
Benefits of Virtualization
Establish or expand a private cloud environment.
* Increase hardware utilization.
* Improve business continuity.
* Establish a centralized desktop strategy.
* Increase efficiency in development and test activities.
The following are top server virtualization product
Amazon Web Services - Elastic Compute Cloud (EC2)
* Vmware – Vsphere
* Microsoft - Hyper-V
Red Hat - Enterprise Virtualization (RHEV)
Server Virtualization Features
Automation of virtual machine provisioning
* Ability to centrally control and optimize the virtual
machine environment
* Ability to backup running virtual machines without
interrupting service
Type I Virtualization (native or bare metal)
Hypervisor layer interacts directly with the computer’s physical hardware for better
performance.
* No host operating system required
* Individual virtual machines have their own OS and accesses hardware through the
hypervisor
* Parent partition creates and manages the child partitions
examples of Type 1 virtualization
VMWare ESXi, Zen & Hyper-V (bare metal)
Type II Virtualization (Hosted)
Requires a Host operating system
* A virtual hardware environment is created for each VM with OS installed.
* The host OS shares access to the computer’s processor with the hypervisor
* Does not provide the same performance as separate physical computers
examples of type II virtualization
VMWare Workstation, Parallel Desktop and Linux KVM
Hyper-v
Hyper-V is Microsoft implementation of server virtualization
Hyper-v
It allows running of multiple operating systems on a physical
server simultaneously.
* Gives virtual machine guests direct access to the host’s
hardware
Possible integration services:
Operating system shutdown
* Time synchronization
* Data exchange
(file interoperability)
Dynamically
expanding
The disk starts with a small size and expands on
demand.
* It can grow to the maximum size.
Fixed size
The size of the VHD file is fixed to the size when
created.
* Faster than a dynamically expanding disk
* Disk uses up the maximum defined space
immediately
Differencing
Disk is linked to another disk (Parent disk)
* Disks include only the differences from parent disk.
* Can save disk space.
* Suitable for multiple virtual machines with similar OS.
Physical (or
pass through
disk)
The virtual machine receives direct access to the
physical disk for exclusive use.
* Provides the highest performance of all disk types
* The drive is not available for other guest systems.
Private switch
Enable communication between
virtual machines on the same host
internal switch
Enable communication between
* VMs on the same host
* VMs to host computer
External switch
VM communicates via physical
network adapter
* Allows communication to external
servers
Check Points (Snapshots)
A Hyper-V checkpoint is an encapsulation of a running
VM’s state, data, and hardware configuration.
