HypervisorOverheads

Hypervisor overhead refers to the additional system resources consumed by a hypervisor to manage and run virtual machines (VMs). A hypervisor, also known as a Virtual Machine Monitor (VMM), is software or firmware that creates and runs virtual machines. It abstracts the underlying hardware and allows multiple operating systems to share a single physical machine.

The overhead can manifest in several ways. Firstly, there is the memory overhead. The hypervisor itself requires a portion of the system's RAM to operate. Additionally, each VM needs its own memory allocation, which the hypervisor manages. Secondly, there is CPU overhead. The hypervisor needs CPU cycles to perform tasks such as scheduling VM execution, managing interrupts, and handling I/O requests. This means that not all of the physical CPU's processing power is directly available to the guest operating systems.

Performance overhead is another significant aspect. When a VM needs to access hardware resources like the network interface or storage, the request typically goes through the hypervisor. This virtualization layer introduces latency and can reduce the overall throughput compared to running directly on bare metal.

The type of hypervisor can influence the overhead. Type 1 hypervisors, also known as bare-metal hypervisors, run directly on the host's hardware, generally resulting in lower overhead compared to Type 2 hypervisors, which run as an application on top of a conventional operating system. Optimizations and advancements in hypervisor technology continually aim to minimize these overheads to improve the efficiency and performance of virtualized environments.