What is a hypervisor
Running only one operating system (OS) on a single computer can lead to wasted resources, especially for software developers. As a result, virtualization technologies that allow a single physical machine to run multiple operating systems have emerged.
Virtualization divides the underlying hardware resources via hypervisors. A hypervisor, also known as virtual machine monitor (VMM), is a software that allows one to create and manage multiple, mutually independent virtual machines (VMs). VMs are logically separated from each other, so that even if one OS crashes for some reason, the other VMs can run unhindered.
Hypervisors are divided into 2 types based on the presence or absence of the underlying operating system:
- type 1 – native/ bare-metal hypervisor
- type 2 – hosted hypervisor
In this article, I will introduce what they are and make a comparison of type 1 hypervisor vs type 2.
What is type 1 hypervisor
Type 1 hypervisors are also known as bare-metal hypervisors, because they run directly on the host’s physical hardware without loading the attack-prone underlying OS, making them very efficient and secure.
Type 1 hypervisors themselves act like lightweight OSs dedicated to running VMs. They may allow only simple server configuration, such as changing IP addresses and passwords.
You need to install a web-based or software management console on another computer to connect to the server remotely, and then create and manage the VMs via the console. In addition, you may need to provide a license fee depending on the features you need.
One of the best features of type 1 hypervisors is that they allow for over-allocation of physical resources. VMs themselves do not consume all the RAM you allocate to them. In fact, they only use the amount of RAM needed to perform specific tasks. That’s why they are resource efficient.
5 type-1 hypervisor examples you must know
1. VMware vSphere/ ESXi
2. Microsoft Hyper-V
3. Citrix XenServer/ Xen
4. Red Hat Enterprise Virtualization (RHEV)
What is type 2 hypervisor
Type 2 hypervisors are also known as hosted hypervisors, because they are installed on existing OSs, and rely on them for virtualization and resource management.
Type 2 hypervisors essentially act like VM management applications running on the existing OS, so you don’t need to install separate consoles on another machine remotely. You can perform most tasks using the free built-in features, making them very cost-effective.
However, they do not have direct access to the host hardware and resources, all hypervisor and VM activities must pass through the host OS, which inevitably results in latency and wasted resources. In addition, security flaws and vulnerabilities in the host OS could potentially compromise all VMs running on it.
You also need to be careful when using type 2 hypervisors to allocate physical resources. VMs will take up all the RAM you allocated to them, and you still need to reserve certain RAM to maintain the running of the host and VMs.
5 type-2 hypervisor examples you must know
1. VMware Workstation/Fusion/Player
2. Oracle VM VirtualBox
3. VMware Server
5. Microsoft Virtual PC
What is the difference between type 1 hypervisor vs type 2
In summary, the main difference between type 1 vs type 2 hypervisors is the presence or absence of the underlying operating system.
Here I make a comparison between type 1 and type 2 hypervisors and summarize the following differences.
|Type 1 hypervisor||Type 2 hypervisor|
|Definition||Runs on bare metal||Runs on an existing OS|
|Virtualization||Hardware virtualization||OS virtualization|
|Security||More secure||Less secure|
|Latency||Lower latency||Higher latency|
|Resource saving||More effective||Less effective|
|Remote console required||Yes||No|
How to choose between type 1 and type 2 hypervisors
When choosing between Type 1 and Type 2 hypervisors, you should start with your needs. Aspects that must be considered include:
- Type and size of the workload
- Security requirements
- Features needed
- Licensing costs
For most times, type 1 hypervisors are suitable for enterprise development environments, or large organizations that need to deploy hundreds of VMs.
Type 2 hypervisors are suitable for personal use, smaller deployments, or multiple-environment test requirements. In addition, some development environments may also need type 2 hypervisors, such as where administrators require access to multiple OSs and their variants, or devices are not dedicated to the VM host roles.
In practical use, VMs can also be converted between type 1 and type 2 hypervisors. For example, convert Hyper-V to VMware or vice versa.
Different data backup strategies for type 1 and type 2 hypervisors
Whether you use type 1 or type 2 hypervisor, you have the need of virtual machine backup. But they do not provide the same data protection solutions.
For administrators using type 2 hypervisors such as VMware workstation, there are not many VMs need to be backed up, and no excessive requirement for downtime. Therefore, you can backup VMware workstation VMs by manually copying the VM files or export VMs to OVF templates.
However, for administrators using type 1 hypervisors, free built-in features are always not enough due to the higher requirements of enterprise development environments. And the license fees for advanced backup features may be uneconomical or just unaffordable.
So, IT staffs often use professional backup tools to compensate for the built-in features. Here I recommend you AOMEI Cyber Backup for the following benefits:
✦ Multiple VMs Backup: with 3 easy steps you can create a complete automatic backup task of multiple, or even all VMs on the host.
✦ Auto Backup and Cleanup: capable of backing up multiple VMs automatically, and cleaning old backup files[link] that exceed the specified retention period.
✦ Offsite Restore: capable of restoring backups to new VMs to another host, or datastore.
✦ Role Assignment: allows one administrator to create sub-accounts with limited privileges, effectively avoid errors caused by others’ mis-operations.
✦ Affordable Pricing: reasonable charges only base on the number of bound devices, regardless of how many VMs are on the host.
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By opening a hypervisor, you open a door to the world of virtualization. No matter you want to create new VMs to run different OSs, or just convert physical to virtual machine, you operate on a hypervisor.
Choosing a suitable hypervisor can increase efficiency and reduce costs. In this article, I introduced what the 2 types of hypervisors are, and made a comparison between type 1 hypervisor vs type 2 for reference.
Type 1 hypervisor is resource effective and secure for separating VMs from underlying OSs, therefore popular among enterprises. However, business data can still be lost due to VM crashes, therefore, taking regular backups is still necessary.