Hypervisors, such as VMware ESXi and Proxmox, provide a layer of virtualization that allows multiple operating systems to run on a single physical server. This offers several advantages over running each operating system on separate physical servers.
Firstly, it enables resource optimization by allowing administrators to efficiently use hardware resources by consolidating multiple workloads on a single server. This reduces hardware costs and energy consumption and enables better data center space utilization.
Secondly, hypervisors provide isolation and security by creating a virtualized environment that isolates each operating system from the others. This means that if one operating system is compromised, it does not affect the other or the host operating system, providing an additional layer of security.
Thirdly, hypervisors offer flexibility and scalability by allowing administrators to easily create and manage multiple virtual machines (VMs). This makes adding new resources or scaling up or down easy based on demand.
Fourthly, hypervisors provide advanced features such as live migration, high availability, and fault tolerance, ensuring VMs remain available even during hardware or software failures. This enables administrators to provide a more reliable and resilient infrastructure.
Lastly, hypervisors provide a centralized management interface that simplifies management tasks, reducing the need for manual intervention and improving productivity.
Using more than one physical server in a hypervisor-based infrastructure provides even more benefits. A cluster of hypervisor hosts can be created, with VMs running on each host. This allows administrators to migrate VMs between hosts for load balancing or maintenance without downtime.
Furthermore, clustering provides redundancy and high availability, ensuring VMs remain available even if a host fails. In addition, clustering can improve performance by providing access to more resources.
However, there are also some disadvantages to running an OS on a hypervisor. One disadvantage is a performance overhead, where running an OS on a hypervisor can result in some degradation in performance compared to running the OS natively on the hardware. This is due to the additional abstraction layer between the OS and the physical hardware.
Another disadvantage is hardware compatibility issues, as hypervisors may not support all hardware devices. This can limit the system's choice of hardware, resulting in additional costs for compatible hardware.
Hypervisors can also be complex to set up and manage, requiring specialized skills and knowledge. This can result in increased training costs and the need for technical staff, which can add to the overall cost of the system.
In addition, hypervisors often require licensing fees, which can add to the cost of the system. The price of licensing can vary depending on the features required and the number of VMs or hosts that need to be licensed.
Finally, since all VMs are running on a single physical server or a cluster of servers, a hardware or software failure in the hypervisor can fail all VMs running on that server or cluster. This can lead to downtime and data loss, making it essential to have a robust backup and disaster recovery strategy.
Overall, while the benefits of running an OS on a hypervisor with multiple servers outweigh the disadvantages in most cases, it is essential to consider these factors when evaluating whether to use a hypervisor-based infrastructure for your organization's IT infrastructure.