What allows multiple operating systems to run on a single physical machine?
Show Understanding virtualisation – How does virtualization help to scale up my organisation?
What is virtualization? Virtualization is essentially a piece of technology that uses software to create an abstraction layer over physical hardware. This creates a virtual compute system, also known as Virtual Machines (VMs). This allows organisations to run multiple virtual computers, operating systems and applications on a single physical server. Imagine the same idea as partitioning a laptop to run Windows and MacOS – essentially by partitioning a physical server, you end up with multiple virtual servers. Simply put, by efficiently using the amount of physical hardware available, it provides a greater return on a company’s investment in return What is a virtual machine? According to IBM, “a virtual machine (VM) is a virtual representation of a physical computer”. An organisation can use virtualization to create multiple virtual machines, with their individual operating systems and applications running all on a single physical machine. Although the virtual machine isn’t able to interact directly with an actual computer, all it needs additionally is a lightweight software called a hypervisor. The hypervisor allows co-ordination between the VM and the physical hardware which it runs on. What is a hypervisor? The hypervisor, essential to virtualization, is a thin layer of software that allows multiple operating systems to run alongside each other while sharing the same physical computing resources. In order to create the ‘partition’, the hypervisor assigns each VM its own portion of underlying computing power, memory and storage, which prevents VMs from interfering with each other. How does virtualization benefit my organisation? Ultimately at the end of the day, businesses and organisations need to adapt to changes in the modern tech environment, and that means streamlining business processes in order to grow and expand. Virtualization indirectly achieves this goal, by reducing costs and improving workflow efficiencies. Virtualization allows organisations to consolidate excess server and desktop hardware, which means reduced costs and lower power consumption fees. Furthermore, the absence of unnecessary physical servers means less floor space required, which translates into costs saved on rent which could be better used elsewhere instead. To mention an excellent example, Microsoft Azure VM is one of the leaders in the world for virtual machines, and has the added advantage of seamless integration with other industry standard Microsoft software. The seamless integration means better workflows, and overall increase in productivity. Find out more about Azure on the Netmarks Singapore website. There are two main hypervisor types, referred to as “Type 1” (or “bare metal”) and “Type 2” (or “hosted”). A type 1 hypervisor acts like a lightweight operating system and runs directly on the host’s hardware, while a type 2 hypervisor runs as a software layer on an operating system, like other computer programs. The most commonly deployed type of hypervisor is the type 1 or bare-metal hypervisor, where virtualization software is installed directly on the hardware where the operating system is normally installed. Because bare-metal hypervisors are isolated from the attack-prone operating system, they are extremely secure. In addition, they generally perform better and more efficiently than hosted hypervisors. For these reasons, most enterprise companies choose bare-metal hypervisors for data center computing needs. While bare-metal hypervisors run directly on the computing hardware, hosted hypervisors run on top of the operating system (OS) of the host machine. Although hosted hypervisors run within the OS, additional (and different) operating systems can be installed on top of the hypervisor. The downside of hosted hypervisors is that latency is higher than bare-metal hypervisors. This is because communication between the hardware and the hypervisor must pass through the extra layer of the OS. Hosted hypervisors are sometimes known as client hypervisors because they are most often used with end users and software testing, where higher latency is less of a concern. Hardware acceleration technology can create and manage virtual resources faster by boosting processing speed for both bare-metal and hosted hypervisors. A type of hardware accelerator known as a virtual Dedicated Graphics Accelerator (vDGA) takes care of sending and refreshing high-end 3-D graphics. This frees up the main system for other tasks and greatly increases the display speed of images. For industries such as oil and gas exploration, where there is a need to quickly visualize complex data, this technology can be very useful. Both types of hypervisors can run multiple virtual servers for multiple tenants on one physical machine. Public cloud service providers lease server space on the different virtual servers to different companies. One server might host several virtual servers that are all running workloads for different companies. This type of resource sharing can result in a “noisy neighbor” effect, when one of the tenants runs a large workload that interferes with the server performance for other tenants. It also poses more of a security risk than using a dedicated bare-metal server. A bare-metal server that a single company has full control over will always provide higher performance than a virtual server that is sharing a physical server’s bandwidth, memory and processing power with other virtual servers. The hardware for bare-metal servers can also be optimized to increase performance, which is not the case with shared public servers. Businesses that need to comply with regulations that require physical separation of resources will need to use their own bare-metal servers that do not share resources with other tenants. |
