What is Server Virtualization?
What is server virtualization?
Server virtualization is a process through which an organization can separate server software from its hardware and create multiple virtual servers with their own operating systems and applications that run on a single physical server. Each virtual server is separated from the others and runs completely independently without compatibility issues. Server virtualization is the underlying basis for cloud computing and enables a variety of hybrid cloud models.
Server virtualization allows organization to cost-effectively support their IT operations and make the most of compute, storage, and networking resources across its entire infrastructure. Because servers rarely use their full processing power around the clock, a lot of server resources aren’t used. In fact, some experts say it isn’t uncommon for a server to be just 15% to 25% utilized at any one time. Servers can sit idle for hours or days as workloads are distributed to a small percentage of an organization’s entire server collection. These idle servers take up precious space in the data center and consume power and IT worker attention and effort in maintaining them.
Through server virtualization, an organization can load a single physical server with dozens of virtual servers (also called virtual machines, or VMs) and ensure that that server’s resources are being used more effectively. Now, a data center can be more efficient with fewer physical machines. Through virtualization, organizations can easily keep resources utilized and dynamically adapt to each workload’s needs as it changes.
What is a virtual server?
A virtual server is a virtualized “instance” on a dedicated physical server. It is an isolated space with its own operating system, policies, applications, and services. Although it acts independently, it resides on a single server with a number of other virtual machines and shares hardware resources with those other machines through the use of a hypervisor. Each virtual server is considered a guest of the main physical server, which is the host.
How does server virtualization work?
An IT administrator can create multiple virtual machines on a single physical server and configure each one independently using a hypervisor. The hypervisor enables the separation of the server’s software from its hardware, the hypervisor acts as a controller and organizes, manages, and allocates resources among all the virtual machines on the host server.
Through abstraction, the hypervisor organizes all the computer’s resources—such as network interfaces, storage, memory, and processors—and gives each resource a logical alias. The hypervisor uses those resources to create virtual servers, or VMs. Each VM is made up of virtualized processors, memory, storage, and networking tools, and while it resides alongside multiple other VMs, it doesn’t “realize” it’s just one of many. It acts completely independently as if it were a single physical server.
Now the organization has a physical server with multiple separate, fully functional computers working within it. The host server can have VMs with differing OSes and a wide variety of applications and systems that might not normally work together.
As the hypervisor monitors and oversees all the host server’s VMs, it can also reallocate resources as needed. If one VM is idle overnight, for instance, its computing and storage resources can be reassigned to another VM that might need extra resources during that time. In this way, the server’s resources are much more fully utilized overall.
VMs can also be moved to other host servers if needed through a simple duplication or cloning operation. The only limit to how many VMs a host server can accommodate is the computer resources it has, so newer computers with more resources can naturally support more VMs.
Server virtualization is a critical component in cloud computing. In fact, many experts consider server virtualization one of the main pillars of cloud computing (along with other components such as automation, self-service, and end-to-end monitoring). Virtualization makes cloud computing possible because it allows a server’s resources to be divided up among multiple VMs and allows organizations to get the ultra-fast scaling they need without giving up workload isolation.
Types of server virtualization
There are five types of server virtualization, distinguished by their approach to isolation, resource management, and interaction with hardware.
Full virtualization (hardware-level) - Creates complete virtual machines with their own operating systems that run independently on a hypervisor. The guest OS is unaware it's virtualized and requires no modification. Modern hypervisors are able to utilize special CPU features (Intel VT-x, AMD-V) to improve virtualization performance and security by allowing the hypervisor to run directly on hardware with processor support.
Para-virtualization - The guest OS is modified to be aware of the virtualization layer, allowing for better performance through direct communication with the hypervisor. Commonly used in Xen environments.
OS-level virtualization (containerization) - Multiple isolated user-space instances (containers) share the same OS kernel. This lightweight approach is highly efficient for running similar workloads.
Hybrid virtualization - Combines multiple virtualization approaches to balance performance, isolation, and resource efficiency based on specific workload requirements.
Server virtualization benefits
Benefits of server virtualization include:
More efficient use of server resources with less need (and cost) of physical hardware
Cost savings through server consolidation, reduction of hardware footprint, and elimination of wasted or idle resources
Enhanced server versatility with the flexibility of creating VMs with different OSes and applications
Increased application performance, thanks to the ability to use VMs for dedicated workloads
Deploy workloads quicker with fast, easy VM duplication and cloning, and flexibility to move VMs to different host servers if needed
Increased IT productivity and efficiency by reducing server sprawl and complex management and maintenance of a large number of physical servers
Added disaster recovery and backup benefits with easy replication of existing VMs, snapshots, and ability to move them as desired
Lower energy consumption by reducing the number of physical machines that take up space and need cooling and power
Reduced security threats due to each VM on a host server being isolated; if one VM is attacked, the others aren’t necessarily compromised
Server virtualization challenges
Despite the many benefits of server virtualization, there are still some challenges:
Software licensing can be complex (and costly) because one physical server might host dozens of different VMs with a wide range of applications and services; for instance, full server virtualization means each VM has its own OS, and each OS requires a separate license.
A host server failure can adversely affect all of its VMs—so 10 applications go down instead of just one, for instance.
VM sprawl can become an issue if IT doesn’t stay on top of where VMs are and how and when they’re being used; it’s so easy to spin up new instances, for instance, that many VMs are used temporarily for testing and then abandoned when no longer needed. But if they’re not actually deleted from the system they could remain in the background and continue to consume power and resources that active VMs need.
If VMs aren’t planned and created with forethought and planning, server performance can slow down if there are too many VMs on the host that need a lot of resources, especially when it comes to networking and memory.
Is server virtualization secure?
Server virtualization does have some inherent advantages when it comes to security. For instance, data is stored in a centralized place that is fairly simple to manage, instead of being left on unauthorized or less-secure edge or end-user devices. The isolation between VMs also helps keep attacks, malware, viruses, and other vulnerabilities isolated as well.
Thanks to virtualization’s granular access control, IT has a higher degree of control over who is able to get to the data stored in the system. Micro-segmentation is often employed to give people access only to specific applications or resources down to the level of a single workload. Also, virtualizing desktops helps ensure that IT personnel stays responsible for updating and patching operating systems and applications—something end users might not stay on top of individually.
Hypervisors reduce security risks with a reduced attack surface in comparison with hardware solutions, thanks to their ability to run on fewer resources. They also update automatically, which helps keep them protected from evolving threats.
On the other hand, server virtualization can present some security risks as well. One of the most common is simply the increased complexity of a virtualized environment. Because VMs can be duplicated and workloads moved to different locations pretty easily, it’s more difficult for IT to adhere to security best practices or even keep to consistent configurations or policies throughout the entire ecosystem.
VM sprawl can also pose a security risk. Those idle and abandoned VMs not only continue to consume resources and power, but they also aren’t likely to be patched or updated—which leaves them vulnerable and a good potential attack risk.
While the isolation between VMs can reduce security risks in one way, it still doesn’t reduce the effect of a distributed denial of service (DDoS) attack. If a DDoS attack affects a VM’s performance by hitting it with a flood of malicious traffic, the other VMs that share that host server’s resources will be affected as well.
IT can reduce the security risks server virtualization presents with some best practices, which include keeping all software and firmware up to date across the entire system, installing and updating antivirus and other software designed for virtualization solutions, stay on top of who’s accessing the system, encrypting network traffic, deleting unused VMs, doing regular backups for VMs and physical servers, and defining and implementing a clear and detailed user policy for VMs and host servers.
Use cases for server virtualization
- Data center consolidation – By virtualizing servers, an organization can reduce its need for physical hardware and also cut down on power and cooling costs.
- Testing environments – It’s so easy to spin up new VM instances and provision them that many organizations are using them for development and testing initiatives.
- Desktop virtualization – Virtualized desktop infrastructure offers the benefits of flexibility, centralized management, increased security, and simplicity.
- Backup and disaster recovery – Virtualization is a great way to approach backup and disaster recovery because it makes it simple to make backups and take snapshots of VMs that can be quickly recovered if disaster strikes.
- Cloud computing – Cloud computing relies heavily on virtualization and automation.
- Increased availability – Live migration of VMs allows organizations to move a VM from one physical server to another without disrupting services. Virtualization also enables business-critical systems and applications to stay up and running even during maintenance cycles or when testing new developments.
- Support for multiple platforms – With virtualization, organizations can run a variety of workloads with differing operating systems without the need for OS-dedicated hardware.
Implementing server virtualization
When planning to implement server virtualization across an organization, there are some important steps to keep in mind. The following are some best practices that can help:
- Create a plan – Make sure all stakeholders have a good understanding of how and why the organization needs a virtualization platform before diving into a full-blown initiative. Consider the costs and potential complexities. How does it fit into your business plan?
- See what’s out there – It’s important to assess the hardware and solutions to get a sense of the scope of your project. What solutions are available? What are your competitors using? Due diligence in this step will go a long way toward a successful implementation.
- Test and experiment – You should try out any potential solution to see how it works in the real world and how it affects your day-to-day operations. Can IT easily manage the work it will create? IT should feel comfortable with any solution before making a purchase decision. They’ll be the ones managing it and keeping it running and should be well aware of the potential pitfalls and challenges any solution will present.
- Consider business needs – Does the proposed solution meet your organization’s unique virtualization needs? How will it affect your IT infrastructure’s security, compliance, disaster recovery plans, and so on? IT should have a deep understanding of the solution’s implications across your entire ecosystem.
- Start small, then scale – If your organization is new to virtualization, it’s smart to experiment with a small deployment on non-critical systems so IT can learn what is required to run and manage it day to day.
- Develop a set of guidelines – You’ll need to put in some thought about VM provisioning, as well as their lifecycles and how they’ll be monitored. Guidelines will help you stay within budgets, avoid wasting resources and VM sprawl, and adhere to agreed-upon behaviors and responsibilities to maintain the system.
- Select the right tools – Even after deciding on a virtualization platform, you’ll need to consider obtaining additional tools to help you leverage the more advanced features of the solution and better manage the system.
- Don’t forget about automation – Make sure IT staff have a good understanding of automation practices and tools because automation goes hand-in-hand with virtualization.
How do I migrate physical servers to VMs?
Migrating physical servers to virtual machines (VMs) is a process known as Physical-to-Virtual (P2V) migration. Here's a step-by-step guide to help you through it:
Preparation
Assess the physical server - Evaluate the server's hardware, operating system, applications, and data to determine compatibility with your virtualization platform.
Choose a virtualization platform - Select a suitable hypervisor (e.g., VMware, Hyper-V, KVM, Nutanix AHV) that supports your server's OS and applications.
Prepare the virtual environment - Set up the virtualization platform, including configuring networks, storage, and any necessary virtual machine templates.
Migration steps
Backup the physical server - Ensure you have a complete backup of the physical server to prevent data loss during the migration.
Use P2V migration tools - Utilize tools provided by your virtualization platform or third-party vendors to perform the migration. Common tools include:
StarWind V2V / P2V Converter (supports multiple hypervisors: ESXi, Hyper-V, oVirt, Proxmox, VirtualBox)
Microsoft Disk2vhd (best for Windows environments)
Open-source tools like Clonezilla, Virt-P2V and OpenQRM.
Perform the migration - Follow the tool's instructions to convert the physical server into a virtual machine. This typically involves creating a virtual copy of the physical server's disk and configuring the VM settings.
Test the VM - After migration, thoroughly test the VM to ensure all applications and services are functioning as expected.
Post-migration
- Optimize the VM - Adjust the VM's configuration for optimal performance on the virtualization platform.
- Decommission the physical server - Once the VM is verified to be working correctly, you can safely decommission the physical server.
How do I migrate physical servers to Nutanix VMs?
Migrating physical servers to Nutanix virtual machines (VMs) requires a Physical-to-Virtual (P2V) conversion process. Because Nutanix Move does not directly support P2V migrations, a third-party tool is necessary to convert the physical machine into a VM format compatible with a Nutanix cluster, which supports both AHV and ESXi hypervisors. Find Nutanix Ready Solutions in the Compatibility Matrix on the Nutanix Portal.
There are two primary methods for this process:
Method 1: Two-Step Migration with VMware Converter and Nutanix Move
This is a commonly recommended approach, particularly when migrating to Nutanix AHV.
P2V conversion - Use VMware vCenter Converter to convert the physical server into a VMware ESXi virtual machine. This serves as a transitional step to virtualize the workload.
V2V migration - Use Nutanix Move to migrate the newly created ESXi VM to the Nutanix AHV cluster.
VMware-based migration workflow - To migrate a server to Nutanix AHV, you first convert it into a VMware-compatible format (like a .vmdk disk). Then, using Nutanix Prism’s Image Service, you import the disk image, and AHV automatically converts it into its native format. Once imported, you can create a new VM using the converted disk. This method simplifies the transition from VMware to Nutanix and ensures compatibility with AHV.
Method 2: Direct P2V Migration with Third-Party Tools
Several third-party tools can migrate a physical server directly to a VM on the Nutanix platform.
Carbonite Migrate - This tool facilitates the migration of both Windows and Linux physical servers. The process typically involves creating a new VM on the Nutanix cluster with a matching OS and configuration, installing Carbonite on the source and destination servers, and then executing the migration.
VMware vCenter Converter - This tool can also migrate a physical server directly to a VMware vSphere VM running on a Nutanix cluster. It is important to review the specific prerequisites and limitations for your software version.
Other Supported Tools - Additional tools mentioned for P2V conversion include HYCU and SureEdge.
Nutanix Professional Services
For organizations requiring assistance, Nutanix offers a Physical-to-Virtual Conversion professional service. This service provides access to skilled consultants who can execute a migration based on a customer-provided plan. The service utilizes supported tools like HYCU, Carbonite Migrate, and VMware Converter to accelerate the conversion of physical machines to VMs on the Nutanix Cloud Platform.
What are some best practices for managing VMs?
While one of the benefits of server virtualization is that it centralizes and simplifies server management, it can also bring some challenges—especially if your IT staff isn’t familiar with virtualization techniques and practices. Here are some best practices for managing VMs efficiently.
Reduce VM sprawl through self-service management – As mentioned previously in this article, it’s very easy to create VMs and even easier to forget about them once they’re no longer active. By relying on self-service VM management, you put the responsibility for deleting those unused VMs in the hands of the end user. Self-service means they have to request their own VMs, which makes it easier for them to manage (and remove) them.
Use templates to right-size VMs – It can be a temptation to create VMs with more resources than they really need. Simply adding CPUs, for instance, won’t necessarily lead to better performance—but it often does lead to wasted resources. Creating VM templates for specific functions can help reduce the tendency to overprovision.
Find the right tools to help monitor performance - The tools that come with your hypervisor and virtualization platform can give you good insight into VM performance. But as environments scale and grow larger, you’ll need more robust tools that can give a deeper view into VMs that aren’t being used as well as information about deployment effectiveness and overall performance.
Provide the appropriate permissions to maintain VM security – In a virtualized environment, IT can delegate management tasks to other users—but it’s important they’re the right users. Make sure you are able to set up a hierarchy that shows which parts of your infrastructure require which permissions. You’ll want to enable simple assignment of permissions as well as equally simple revocation of permission when needed.
Enable remote access through VPN and multifactor authentication – As hybrid work models have led to more people working from home, it’s important to have a good way to access the virtualized environment remotely. A VPN connection with multifactor authentication is recommended.
Use a backup and restore platform designed for VMs – When backing up a host server with VMs, be sure to choose a backup platform that gives you the ability to restore individual VM files.
How does Nutanix monitor and optimize VM performance?
Nutanix provides three core products for VM performance monitoring and optimization: Intelligent Operations delivers AI-powered analytics and automation, Nutanix Insights provides predictive health monitoring and support, and Prism Central offers centralized multi-cluster management - all working together to help you spot and resolve performance bottlenecks before they impact users.
Category | Product | What it measures | Why it matters |
|---|---|---|---|
Multi-cluster management | Multi-cluster monitoring & control, latency heat maps, VM/host contention, run-way capacity. | Lets you pivot from a noisy VM straight to the noisy host across dozens of sites. | |
AIOps & automation | ML-driven anomaly detection & predictive alerts, capacity forecasting & planning, VM right-sizing recommendations, bottleneck detection with optimization, low-code remediation workflows. | Watches every VM’s baseline and auto-opens Jira/ServiceNow tickets when behavior drifts. | |
Predictive health & support | Periodic automated health checks, automatic support case creation, proactive log collection, security advisories & recommendations. | Proactively flags latent issues and clusters them on a single dashboard—no local hardware required. |
Nutanix and server virtualization
Nutanix understands server virtualization and how it enables and enhances an organization’s ability to work productively. We have a range of virtualization tools and solutions designed to simplify the entire process, from deployment to day-to-day management.
With Nutanix AHV, you can enjoy all the benefits of virtualization without compromise. Built for today’s hybrid cloud environments, AHV makes the deployment and management of VMs and containers easy and intuitive. With self-healing security and automated data protection with disaster recovery, rich analytics, and more, it’s everything you need without the cost and complexity.
