IBM Cloud Virtual Servers for Classic

Choosing a virtual machine over a physical one, also known as a bare metal server, is less about competing capabilities and more about knowing what you need, when you need it.

Bare metal servers are all about raw hardware, power and isolation. They're single-tenant, physical servers completely void of hypervisor cycles (virtualization software), and entirely dedicated to a single customer — you.

Workloads that highly prioritize performance and seclusion, like data-intensive applications and regulatory compliance mandates, are typically best suited for bare metal servers — especially when deployed over sustained periods of time.

ERP, CRM, SCM, e-commerce and financial services applications are just a few workloads ideal for bare metal servers.

So when would you place a hypervisor on top of the bare metal hardware to make a virtual machine? When your workloads demand maximum flexibility and scalability.

Virtual machines effortlessly drive up server capacity and increase utilization — ideal for moving data from one virtual machine to another, resizing data sets and dividing dynamic workloads.

When a hypervisor is used on a physical computer or server (also known as bare metal server), it allows the physical computer to separate its operating system (OS) and applications from its hardware. Then, it can divide itself into several independent "virtual machines" or VMs.

Each of these new VMs can then run their own OS and applications independently while still sharing the original resources from the bare metal server, which the hypervisor manages. Those resources include memory, RAM, storage and the like.

The hypervisor acts like a traffic cop of sorts, directing and allocating the bare metal's resources to each of the various new VMs, ensuring they don't disrupt each other.

There are two primary types of hypervisors.

Type 1 hypervisors run directly on the physical hardware (usually a server), taking the place of the OS. Typically, you use a separate software product to create and manipulate VMs on the hypervisor. Some management tools, like vSphere from VMware, let you select a guest OS to install in the VM.

You can use one VM as a template for others, duplicating it to create new ones. Depending on your needs, you might create multiple VM templates for different purposes, such as software testing, production databases and development environments.

Type 2 hypervisors run as an application within a host OS and usually target single-user desktop or notebook platforms. With a Type 2 hypervisor, you manually create a VM and then install a guest OS in it. You can use the hypervisor to allocate physical resources to your VM, manually setting the amount of processor cores and memory it can use. Depending on the hypervisor's capabilities, you can also set options like 3D acceleration for graphics.

For a full overview of hypervisors, check out Hypervisors.

VMs have several uses, both for enterprise IT administrators and users. Here are a few options:

• Enable cloud computing: For more than 10 years, VMs have been the fundamental unit of compute in cloud, enabling dozens of different types of applications and workloads to run and scale successfully.
• Support DevOps: VMs are a great way to support enterprise developers, who can configure VM templates with the settings for their software development and testing processes. They can create VMs for specific tasks such as static software tests, including these steps in an automated development workflow. This all helps streamline the DevOps toolchain.
• Test a new operating system: A VM lets you test drive a new OS on your desktop without affecting your primary existing one.
• Investigate malware: VMs are useful for malware researchers that frequently need fresh machines on which to test malicious programs.
• Run incompatible software: Some users may prefer one OS while still needing a program that is only available in another. One good example is the Dragon range of voice dictation software. Its vendor, Nuance, has discontinued the macOS version of its product. However, running a desktop-focused hypervisor — such as VMware Fusion or Parallels — enables you to run Windows in a VM, giving you access to that version of the software.
• Browse securely: Using a VM for browsing enables you to visit sites without worrying about infection. You can take a snapshot of your machine and then roll back to it after each browsing session. This is something a user could set up themselves using a Type 2 desktop hypervisor. Alternatively, an admin could provide a temporary virtual desktop located on the server.