What is Virtualization?
The procedure of operating a virtual interface instance of a computer system in a separate layer from the actual hardware is known as virtualization. It usually refers to running more than one operating system on the same machine at the same time.
Figure 1. What is Virtualization
It may appear to applications running on top of the virtualized computer that they are functioning on their own dedicated machine, with their own libraries, operating system, and other separate programs from the host virtualized system.
Industry experts are more widely utilizing virtualization technology software, which has already become an indispensable tool for many of them.
What does virtualization mean?
Virtualization is the cornerstone of cloud computing since it allows for more efficient use of actual computer hardware. Even though it is only running on a piece of the real underlying computer hardware, each VM runs its operating system and behaves like an independent machine.
As a result, virtualization allows for more efficient use of physical computer hardware and a higher return on a company's hardware investment.
Virtual machines can access a variety of resources, including computing power via hardware-assisted but limited access to the host machine's CPU and memory; one or more physical or virtual disk devices for storage; a virtual or real network interface; and any shared devices like video cards, USB devices, or other hardware.
However, a disk image is used to describe a virtual computer that is kept on a virtual disk. That disk image can contain the data necessary for a virtual computer to boot and any additional storage requirements.
History of Virtualization
These days, virtualization is all about over-place computing systems. It is about clouds, hypervisors, remote desktops, among many other virtual technologies; it's critical to remember where it all began.
Even though it may appear that virtualization became popular only a few years ago, it has been around for over 50 years! The origins of virtualization may be traced back to IBM in the 1960s when programmer Jim Rymarczyk was heavily involved in the first mainframe virtualization project.
Project MAC was announced on July 1, 1963, by the Massachusetts Institute of Technology (MIT) (Mathematics and Computation, later renamed to Multiple Access Computer). DARPA awarded this project a $2 million funding to advance computer research, especially in the fields of OS, AI, and Computational Theory.
MIT required new computer hardware capable of supporting many simultaneous users as part of this research funding and solicited offers from a variety of computer suppliers, including General Electric (GE) and International Business Machines Corporation (IBM).
IBM was hesitant to commit to a time-sharing computer at the time because they did not believe there was sufficient demand, and MIT did not want to utilize a specially customized machine. GE, on the other hand, was ready to commit to developing a time-sharing computer. As a result, MIT picked GE as their preferred vendor. The loss of this chance served as a wake-up call for IBM, which began to realize the demand for a system like this. Particularly when IBM learned about Bell Labs' requirement for a comparable system.
Later in 1990, Sun Microsystems started a project called Stealth. Engineers working on Stealth were dissatisfied with Sun's usage of C/C++ APIs and believed there was a better method to create and run programs. The project was renamed numerous times over the following few years, including Oak, Web Runner, and eventually Java in 1995.
Java was aimed for the World Wide Web in 1994 because Sun regarded it as significant growth potential. The internet is a vast network of machines that operate on many operating systems, and there was no way to execute rich programs across all of them at the time. Java was the solution to this problem. The Java Development Kit (JDK) was published in January 1996, allowing developers to create Java Platform applications.
With growing complexity came higher administrative costs due to the need to engage more skilled IT experts and the requirement to perform a wide range of activities, such as Windows Server backup and recovery. Many IT budgets couldn't support these initiatives since they needed additional manual engagement in processes. Server maintenance expenses were rising, particularly those related to Windows Server Backup, and more employees were needed to complete a growing number of daily activities. The challenges of limiting the effect of server failures, improving business continuity, and developing more comprehensive disaster recovery strategies were all equally essential.
Computer virtualization has a long and illustrious history that dates back nearly half a century. It may be used to make programs simpler to access from afar, let them operate on more platforms than they were designed for, improve stability, and make better use of resources. Virtual Desktops, for example, may be dated back to the 1960s, whereas virtualized apps, for example, can only be traced back a few years.
How Does Virtualization Work?
Virtualization separates an application, a guest operating system, or data storage from the underlying hardware or software. Moreover, server virtualization, which employs a software layer called a hypervisor to simulate the underlying hardware, is widespread use of virtualization technology.
Memory, input/output (I/O), and network traffic are frequently included. In virtualization, the role of the hypervisor is to take physical resources and divide them so that the virtual environment may use them. They can run on top of an operating system or be installed directly on the hardware. The majority of businesses choose the latter method to virtualize their systems.
While the performance of these virtual machines may not be as good as that of an OS operating on real hardware, it is sufficient for most systems and applications. This is because most systems and applications do not utilize or need the full use of the underlying hardware. When this reliance is removed, virtual machines (as a result of virtualization) provide better isolation, flexibility, and control to their clients.
The process flow of virtualization is given below-
- First, the physical resources are separated from their physical surroundings by hypervisors.
- After that, the real environment's resources are taken and distributed as needed amongst the multiple virtual environments.
- Thirdly, users interact with the virtual world and do operations there.
- Finally, when the virtual environment is up and operating, a user or program can provide a command that necessitates the usage of actual resources. The hypervisor responds by relaying the message to the physical system and recording the changes. This will take place at a near-native pace.
What are the features of Virtual Machines?
The most important features of virtual machines are sharing, aggregation, emulation, and isolation. Within the same host, virtualization permits the development of several computer environments. This simple functionality is intended to restrict the number of active servers and save energy.
In short, virtual machines increase the profitability of infrastructure and resources by using them in a better way. Using a variety of different operating systems (Linux, Mac OS, Windows)
lowering the hardware's operating expenses (in electricity, server leasing, cooling, etc.) virtual machines allow quick deployment, hardware development flexibility, load balancing, and improvised security.
Let's have a look at the four most important features of virtual machines-
1. Efficiency of resources
Considering the application server, it required its own dedicated physical CPU before virtualization for each application server. IT personnel had to buy and set up a new server for each program they intended to run. (For dependability reasons, IT preferred one application and one operating system (OS) per machine.) Each physical server would invariably be underutilized. On the other hand, server virtualization allows running several programs on a single physical machine (usually an x86 server) without losing dependability. This allows the use of the computational capability of the physical hardware.
2. Faster provisioning
It takes time to buy, install, and configure the hardware for each application. Provisioning virtual machines to execute all of your apps is considerably faster if the hardware is already in place. You may even use management software to automate it and incorporate it into current procedures.
3. Minimize downtime
Operating system and application failures can create downtime and impede user productivity. Admins can operate numerous redundant virtual machines side by side and failover between them if one fails. It is more costly to run many redundant physical servers.
4. Easy administration
Using software-defined VMs instead of real machines makes it easier to utilize and maintain policies established in software. This enables you to design IT service management procedures that are automated. For example, administrators can use automated deployment and configuration tools to establish groups of virtual machines and apps as services in software templates. This means they may install such services regularly and consistently without going through the tedious and time-consuming process each time. Manual setup is time-consuming and prone to errors. Administrators may use virtualization security rules to impose specific security configurations based on the virtual machine's function.
What are the Benefits of Virtualization?
The following are some of the key advantages of r virtualization;
Figure 2. Benefits of Virtualization
1. Security enhancement
The ability to manage transparently, execution of guest applications offers new options for a secure virtual interface as well as a controlled execution environment. Guest programs typically conduct all of their activities against the virtual machine, which subsequently interprets and applies them to the host applications.
A virtual machine manager may monitor and filter the behavior of guest programs, preventing some potentially hazardous processes.
The host's resources can then be concealed or merely shielded from the visitor. When working with untrusted code, increased security is a must.
2. Execution management
Virtual machines provide the necessary capability to run complete operating systems. A hypervisor leverages native execution to share and control hardware, allowing different environments to operate on the same physical system while being separated from one another. Virtualization-specific hardware, typically from the host CPUs, is used by modern hypervisors for hardware-assisted virtualization.
In addition, process virtual machines run in a platform-agnostic environment.
Depending on the sort of virtualization in question, the idea of portability can be used in various ways.
When using a hardware virtualization solution, the guest is packed into a virtual image that can be securely transferred and performed on top of other virtual machines in most instances.
The binary code representing application components (jars or assemblies) can execute without recompilation on any implementation of the appropriate virtual machine in the case of programming-level virtualization, such as that provided by the JVM or the .NET runtime.
The virtualization layer, which is ultimately software, controls the environment in which guest applications run. In addition, a totally distinct environment can be simulated in relation to the host, allowing the execution of guest programs that require certain features not available in the actual host.
Within the same host, virtualization permits the development of several computer environments. This simple functionality is intended to restrict the number of active servers and save energy.
Virtualization provides for the sharing of physical resources among several guests and allows for aggregation, which is the opposite process.
A collection of individual hosts can be linked together and displayed to visitors as a single virtual host. Cluster management software, which harnesses the physical resources of a homogenous collection of machines and displays them as a single resource, is used to accomplish this capability.
Virtualization allows operating systems, programs, and other things to run in a fully independent environment. The guest application interacts with an abstraction layer, which gives access to the underlying resources to carry out its task. The virtual machine can filter the guest's behavior, which can prevent dangerous attacks on the host.
8. Performance tweaking
Aside from these features, virtualization also enables performance tweaking, which is an essential capacity. Given the significant advancements in hardware and software that allow virtualization, this capability is currently a reality.
By fine-tuning the attributes of the resources accessible through the virtual environment, it becomes easier to regulate the guest's performance. This feature enables the implementation of a quality-of-service (QoS) framework.
What are the Disadvantages of Virtualization?
It's essential to think about the different upfront expenses when migrating to a virtualized environment—virtualization software and any additional hardware that may be required to make virtualization viable can be pricey.
If the present infrastructure is older than five years, a budget for the first renewal will be required. Fortunately, many organizations can accept virtualization without having to spend a lot of money.
Additionally, prices can be reduced by working with a managed service provider that offers monthly lease or purchase alternatives.
A virtual machine is less efficient in terms of hardware accessibility. It is unable to gain direct access to the hardware. Furthermore, for most IT businesses, its speed is insufficient. As a result, they employ a system that is both virtual and physical in nature.
Infections can readily damage a weak host system. This generally occurs when the operating system contains bugs. If two or more virtual computers are connected, the diseases will spread to other virtual machines as well.
Although the machines are virtualized in a virtual machine, the host machine's resources are still used. To manage many virtual machines on a single host computer, the computer must be strong enough. It will create performance difficulties if its power is insufficient.
A virtual machine is a sophisticated piece of software. Its complexity stems from the fact that it is equipped with several local area networks. As a result, in the event of a failure, pinpointing the source of the problem will be challenging, especially for those who are familiar with the virtual machine's structure and hardware.
What is Virtualization Used for?
Virtualization can help in the reduction of physical space. Each server in a traditional data center is typically dedicated to a single application. As a result, most computers are underutilized. Virtualization allows more workloads to be performed on a single server, reducing the number of physical computers required.
Moreover, hardware is frequently the most expensive component in a data center. Virtualization lowers costs by eliminating the requirement for physical computers. However, the cost is not limited to hardware; software license savings, power and cooling cost reductions, and enhanced user accessibility and performance are also examples of methods to save costs.
Furthermore, cloning an image, master template, or existing virtual machine to have a server up and operating in minutes is possible with virtual machines. This is in contrast to physical servers, which often take several hours to set up.
Lastly, virtualization allows the generation of complete backups of virtual computers in minutes. These backups may be easily transferred from one server to another and re-deployed. Virtual machines may take a snapshot of a virtual machine.
Which Virtualization Software is Best?
Virtualization may be used in a variety of settings, including the home office and small business, as well as big corporations and data centers. It's critical to use the proper software to handle those virtualizations—if you don't, your virtual environment will be cluttered and ineffective at best and unstable and non-functional at worst.
Figure 3. Which Virtualization Software is best?
1. VMware Workstation Player
On a single PC, VMware Workstation Player allows you to run a second, separate operating system. Workstation Player leverages the VMware vSphere hypervisor to deliver a simple yet mature and stable local virtualization solution with numerous uses ranging from a personal, educational tool to a business tool for giving a simpler experience to run a corporate desktop on a BYOD.
Pros: A great application for testing new operating systems, such as Linux. It may be used to access onion networks or view websites you don't trust, minimizing the danger. It does not require sophisticated knowledge on the part of the user. It's simple to set up a vmware virtual machine and utilize.
Cons: The operating system's performance will never be the same as a native installation, which is a drawback not only of VMware workstation but of all virtualized environments.
VirtualBox is a cross-platform virtualization program that allows you to run different operating systems on one machine simultaneously. It also supports the OVF file type as well as VM group control.
Pros: It helps to handle numerous virtual machines, manage multi-screen resolutions, connect with iSCSI storage servers, and more. It is designed for corporate and household usage.
Cons: Setting up a Guest OS with VirtualBox is pretty challenging, especially if you want to enable access to Host OS devices like a printer. Switching between Host OS and Guest OS also takes a long time.
3. Parallels Desktop
Parallels Desktop is a Mac virtualization program that uses hypervisor technology to directly transfer the host hardware resources to the virtual machine's resources. As a result, each virtual machine behaves exactly like a standalone computer, with nearly all of the resources of a physical computer.
Pros: It supports a variety of guest operating systems on macOS, including Windows, Linux, and Android. It provides for simple peripheral switching and integration with the start menu.
Cons: The integration method is appropriate, although it may be a little perplexing for novice users at times. In comparison to other applications, it consumes more power/battery.
4. Citrix Hypervisor
Citrix Hypervisor is an open-source virtualization technology that is extremely dependable and secure for cloud, server, and desktop virtualization infrastructures.
Pros: As an open-source product, there are no concerns with vendor lockdown. It enables live VM migration, allowing you to keep systems up and running while making hardware changes in the background.
Cons: Although some of this application is free, the free version has restrictions that force most medium and large businesses to acquire the premium version. Moreover, virtual networks and networking are not as stable as they should be.
5. Microsoft Hyper-V
Hyper-V is Microsoft's native hypervisor for generating and maintaining virtual machine (VM) environments, often known as a bare-metal hypervisor. On a single physical server, it runs numerous operating systems.
Hyper-V isolates each virtual computer within the same physical machine, allowing various users to access different systems on the same hardware separately.
Pros: Because of its isolation capability, even if one virtual machine dies, it does not affect other workloads operating on the same physical system.
Cons: Hyper-V is not suitable for operating systems other than Windows. Automatic load balancing might be better, as it interferes with other virtualization applications.
QEMU is a hosted virtual machine monitor that uses dynamic binary translation to simulate the machine's CPU and provides a range of hardware and device models for the machine to run several guest operating systems.
It may also be associated with the Kernel-based Virtual Machine (KVM) to run virtual machines at near-native speeds by using hardware extensions.
Pros: It gets excellent results by utilizing dynamic translation. When used as a virtualizer, it provides near-native speed since the guest code is executed directly on the host CPU. When running under the Xen hypervisor or with the KVM kernel module in Linux, it allows virtualization.
Cons: Support for Microsoft Windows and other host operating systems is insufficient. Installing and using it is more complex than with comparable emulators.
7. Xen Project
Server virtualization, infrastructure as a Service (IaaS), desktop virtualization, security applications, embedded and hardware appliances, and automotive/aviation are all areas where the Xen Project is working to further virtualization.
Pros: Xen hypervisor can be used to consolidate multiple virtual machines onto a single hardware platform. As a result, there are space and energy savings that can add up to significant savings.
Cons: Xen does not provide a large number of simple administration tools, and users should anticipate the same management tools that you would find in most other open-source software. Although command syntax and how-to options are widely available on the internet, the use of the command line needs prior experience.
8. Proxmox VE
For corporate virtualization, Proxmox Virtual Environment is a full open-source server management platform. On a common network, it closely combines the Kernel-based virtual machine hypervisor with Linux Containers that defines storage and networking functionalities.
Pros: A high-availability cluster is easy to set up. Although Proxmox VE is capable of running on a single server, it may also be installed on many servers to form a cluster.
It runs on a Debian base system with an Ubuntu kernel. This ensures that everything related to the underlying operating system has been thoroughly tested.
Cons: Forwarding resources from a local host machine to a virtual server, such as graphics, and other components, is more difficult than with other virtual machines.
Furthermore, community forum support might be improved. Paid support plans are available, however new customers who are just getting started with the program will not have access to them.
What Are The Types of Virtualization?
1. Data Virtualization
Data virtualization is a contemporary data layer that allows users to access, integrate, transform, and deliver datasets at unprecedented speed and cost.
Users may quickly access data stored throughout the organization, including traditional databases, big data sources, cloud, and IoT devices, utilizing data virtualization technology, which takes a fraction of the time and expense of physical warehousing and extract/transform/load (ETL).
Users may utilize data virtualization to apply a variety of analytics to fresh, real-time data updates, including graphical, predictive, and streaming analytics. Data virtualization customers can be confident that their data is consistent, high-quality, and secure thanks to integrated governance and security. Furthermore, data virtualization enables more business-friendly data by converting native IT structures and syntax into simple, IT-curated data services that are easier to locate and use via a self-service business directory.
2. Desktop Virtualization
Desktop virtualization is a process that isolates a user's PC programs from their desktop. Virtualized desktops are often hosted on a remote central server rather than on a personal computer's hard disk. Desktop virtualization is sometimes known as client virtualization since it uses the client-server computing architecture to virtualize desktops.
Users can keep their own desktops on a single, central server using desktop virtualization. Users can connect to the central server via a local area network (LAN), a wide area network (WAN), or the internet.
Desktop virtualization has several advantages, including lower total cost of ownership (TCO), greater security, cheaper energy costs, less downtime, and centralized administration.
3. Network Functions Virtualization (NFV)
The decoupling of network services from proprietary hardware appliances and executing them as software in virtual machines is known as Network Functions Virtualization (NFV).
Virtualized networking components are used in NFV to enable a hardware-independent infrastructure. Compute, storage, and network operations may all be virtualized and deployed on commercial off-the-shelf (COTS) hardware, such as x86 servers. Because virtualized resources are accessible, VMs may be allocated portions of the x86 server's resources.
4. Operating System Virtualization
By separating applications from the operating system, operating system virtualization offers users application-transparent virtualization. By allowing for the seamless transfer of individual apps, the OS virtualization approach provides granular control at the application level. The finer granularity migration provides more flexibility and lowers overhead.
OS virtualization may also be used to move essential programs to another operating system instance that is currently executing. Patches and upgrades to the underlying operating system are applied in a timely manner, with little or no impact on application service availability.
5. Server Virtualization
The technique of dividing a single server into several tiny, isolated virtual servers is known as server virtualization. This technique does not necessitate the purchase of new or additional servers; rather, virtualization software or hardware splits an existing server into many isolated virtual servers. Each of these is able to function on its own.
Servers are the pieces of software that store and serve data and applications and provide functionality to other programs. In a local area network (LAN) or a wide area network (WAN), this device handles requests and distributes data to other computers (WAN). Servers are frequently quite powerful, capable of handling complicated tasks with ease.
6. Storage Virtualization
Storage virtualization combines several physical storage arrays from SANs into a single virtual storage device. The pool may combine disparate storage devices from various networks, suppliers, or data centers into a unified logical perspective and control it all through a single window.
Virtualizing storage isolates the storage management software from the underlying hardware architecture to give more flexibility and scalable pools of storage resources. It may also abstract storage hardware (arrays and drives) into virtual storage pools, similar to computing virtualization abstracts compute hardware (servers) into virtual machine instances.
What is a Virtual Machine?
A virtual machine (VM) is software that allows running programs or applications without having to connect to a real system. One or more guest computers can operate on a physical host computer in a VM instance.
Although they are on the same physical host, each VM has its own operating system and operates independently of other VMs. Virtual machines (VMs) are often operated on servers, although they may also be run on desktop computers or even embedded devices. Multiple VMs can share physical host resources like CPU cycles, network bandwidth, and memory.
In general, there are two sorts of virtual machines: process virtual machines and hypervisors. Process virtual machines isolate a single process, and virtual machines isolate the operating system and applications entirely from the actual computer. Hypervisors are used by system VMs as a middleman, allowing software to access hardware resources.
Does Virtualization Slow Down Computers?
No. In fact, virtualization doesn't affect computer performance. Moreover, virtualization does not require a lot of resources; it will not slow down the host machine. When a computer slows down, it's usually because the hard disk, CPU, or RAM is overworked.
The entire goal of virtualization is to make the VM run quicker and better. If you turn off virtualization, the VM (when you decide to use it) will consume more system resources, slowing everything down.
Depending on the type of virtualization utilized, and workload, virtualization adds various levels of overhead. If an application spends the majority of its time executing instructions rather than waiting for external events like user interaction, device input, or data retrieval, it is considered CPU-bound.
The virtualization overhead for such programs comprises the additional instructions that must be performed. This overhead consumes CPU processing time that the program could otherwise use. Virtualization overhead almost always results in a decrease in overall performance.
What Factors Need to be Considered to Make a Virtual Machine?
One thing is clear when it comes to servers used by large, medium, and even small businesses: they must be strong enough to execute any operation or job mandated by current IT requirements. Consider the following factors when building a virtual machine-
The advantage of virtualization is that the hardware requirements are very simple. This technology will run on any sort of hardware as long as it has enough RAM and processing power to handle the unique guest environments you wish to build. This implies that new hardware may be tuned to offer the performance of a dedicated server, while existing gear can be better leveraged to consolidate resources and save maintenance and upgrade expenses.
It's helpful to realize that there are numerous alternatives accessible if you're seeking capable software. You have suppliers like VMware, Microsoft, and Red Hat, as well as their various solutions for servers, PCs, apps, and a variety of other niches. The greatest thing MSPs on the lookout for can match software to their unique requirements and assign a skilled IT professional to find it.
Dealing with storage for a virtual infrastructure is one of the most difficult management tasks that IT managers face. Managed service providers should investigate cloud computing, storage appliances, and other technologies to ensure that they have the capability to support a fully functional virtual environment. MSPs will be stuck with a complicated solution that almost totally lacks the advantages they're after if the storage problems aren't solved.
Virtualization, despite its immense capacity, cannot overcome the constraints of physical machines. While a single server might theoretically host hundreds of virtual computers, this isn't the best option, especially when it comes to catering to customers. Not only do you have to account for your web servers, control panels, and database systems, but you also have to account for the technologies your clients wish to use, which might include a slew of resource-intensive apps that use a lot of physical hardware. In other words, be realistic about your hardware's capabilities and avoid the urge to go crazy.
5. System Failure
Certain organizations are implementing virtualization in order to reduce risks and improve availability. It is possible, but poor execution might actually increase the chance of failure. Although the idea is to help technology reach its full capacity, the fact that you're asking it to carry a heavier physical load increases the risk of failure. A disaster recovery strategy that involves backing up and restoring data on virtual systems should be developed to guarantee that customers have as few interruptions as possible.
How to Open Virtual Machine Firewall?
You can set up incoming and outgoing firewall connections from a virtual machine for a service or a management agent.
VMware ESXi allows firewall management from the user interface. The ESXi firewall is set to block all incoming and outgoing traffic without the services that are allowed in the host's security profile at the time of installation.
To configure the firewall in VMware ESXi, first browse the host inventory, go to the Configure menu, and click the Firewall option under the system.
In VirtualBox, you may utilize the OPNsense firewall to secure your virtual machine's internet connection.
First Network Adapter: You must choose your own network adapter. In Bridge Mode, it will connect directly to the internet connection.
Second Network Adapter: Choose Microsoft Loopback as the second network adapter. OPNsense will provide us with an internet connection.
After installing OPNsense, go to the DHCP settings in the OPNsense WEB GUI and set a fixed IP for your PC.
Finally, your computer will connect to the internet via two different operating systems.
What Can You Do With Virtualization?
1. Access virus-infected data
Have you ever been emailed a file that your antivirus program has detected, but that includes vital information that you need to see? Virtualization software typically contains snapshot capabilities, which allow you to generate a "saved state" of the virtual OS and its whole hard drive. It's kind of going back in time.
You might make a virtual machine snapshot, open the infected file within the VM to access the data, and then simply click to restore the VM image.
2. Software testing
You might utilize your virtual PC to test new software, upgrades, or even new software settings before releasing them on your primary operating system.
Some server administrators use virtualization to make a duplicate of an existing operating system installation, including its data, which they then run virtualized and test to determine whether any configuration changes or upgrades would affect the system.
You could do the same thing if you manage workstation machines and want to make sure a Windows update is working before deploying it—just test it first in a virtualized system.
3. Personal Cloud Computer
There's no need to bring your laptop with you if you're out of the workplace. Simply leave it running (with power saving switched off! ), take your phone or tablet computer, and connect to the laptop over the internet through a Remote Desktop Protocol (RDP) connection. This will provide you access to the same desktop environment as before, but without the flashy visuals.
4. Run two or more OS simultaneously
Want to test Linux or FreeBSD, but don't want to mess with partitioning your computer's hard drive? You may run just about any operating system inside a virtual machine, including most Linux distributions, as long as it would normally install on your computer.
For years, Linux and Mac users have used virtualization to run Windows on top of their preferred operating system.
5. Full OS Backup
Backing up the virtual OS is as easy as backing up any other file because it is fully contained within a sequence of files. The same is true for virtualized server deployments. Suppose you're using a virtual machine on a server to host your mail server, and it gets hacked. In that case, you need to restore the backup files to get everything as it was before and running.