A hypervisor, also known as a Virtual Machine Monitor (VMM), is a software layer that abstracts hardware from the operating system. It enables multiple guest operating systems to run simultaneously on a single physical host by partitioning CPU, RAM, and storage resources into isolated environments.
Hypervisors are categorized into two types. Type 1 (bare-metal) runs directly on the host hardware (e.g., Microsoft Hyper-V or Proxmox VE). Type 2 runs as a software layer on top of a conventional operating system. The hypervisor manages the execution of guest instructions and ensures that memory spaces remain strictly separated to prevent cross-VM interference.
This technology is essential for server consolidation, building IaaS cloud infrastructures, and application sandboxing. It facilitates rapid scaling and hardware-independent workload migration. Modern hypervisors leverage hardware-assisted virtualization like Intel VT-x to minimize performance overhead.
Performance Fact
Modern Type 1 hypervisors typically introduce an overhead of less than 5% for most compute-intensive tasks. By using virtio drivers for network and disk I/O, administrators can further reduce latency, making virtualized environments suitable for high-load production databases.