The transition to virtual servers (VPS) is an avalanche-like process that cannot be stopped. More and more private users and commercial companies are resorting to this means of using computing power. And this is not surprising, because virtual machines can significantly save money, which is perhaps the main interest of any business project. In addition, virtualization offers a number of significant advantages.
- Cost reduction. Minimizing costs and, as a result, maximizing profits is the holy grail of any business. Switching to virtual servers relieves an enterprise of the burden of buying expensive hardware to organize its own cyber ecosystem. This allows businesses to save twice: physical computing equipment is not only quite expensive in itself, but also requires space for its physical placement. And this is not just a room, but the highest requirements for environmental conditions – temperature, humidity, ventilation. With the transition to virtual servers, these costs become a thing of the past.
- System adaptability. Doing business places the highest demands on the efficiency of responding to environmental challenges. Using a VPS allows you to simultaneously use different operating systems on the same physical media due to the placement of several virtual servers on it. There is no need to change or reconfigure hardware to use, test, or develop different programs.
Read also: How to choose a VPS
Let us consider some of the most popular virtualization solutions.
KVM
KVM (Kernel-based Virtual Machine) is a software solution that supports hardware virtualization, allowing you to run any operating system (BSD, Windows or Linux) from a disk image or a template. And it does so with virtually no performance degradation. One of the advantages is the high degree of confidentiality achieved through data separation: information placed on one of the virtual servers remains securely hidden from users of other VSDs, despite the fact that the data is physically located on the same hard drive.
As mentioned above, KVM is based on hardware virtualization: an OS installed on a physical medium software emulates the physical medium, which, in turn, is used to “roll up” the user’s operating system and install applications. When running several OSes, the Kernel-based Virtual Machine acts as a hypervisor for monitoring resource allocation.
Under high load, you can notice a certain decrease in performance, which is not critical. However, this is relevant only up to a certain limit: as soon as the excess load exceeds the limit, a cascade of process shutdowns begins, which without administrator intervention can lead (and usually does) to a server crash. This factor is the main disadvantage of KVM, which limits the scope of its application to projects that are not very demanding (relatively) in terms of resources.
KVM is the optimal solution for effective monitoring, as each process is associated with a separate host. This makes it possible not only to quickly identify the location of the problematic process, but also to shut it down.
At the moment, KVM is under active development (although it is a perfectly working solution), but despite this, many people prefer it. This is due to its main advantages: high flexibility and performance, albeit with the aforementioned limitations.
OpenVZ
OpenVZ, the brainchild of SWSoft Inc, is an operating system-level virtualization tool. Without going into details, we can say that it opens up huge scaling opportunities: the number of fruitful virtual copies of the server is limited only by the natural limitations of the physical medium. Namely, the amount of its RAM and the computing power of the CPU.
Another limitation is related to the fact that OpenVZ is developed on the basis of the Linux kernel. It follows that any of the many virtual servers also requires the installation of this particular OS, although it allows the user to choose a specific build. But many users do this for a simple reason: in terms of disk access speed and, as a result, overall performance, OpenVZ simply leaves no chance to the other heroes of our review – KVM and XEN.
Unfortunately, the level of privacy is a bit of a complaint: despite the fact that virtual servers are isolated from each other, all processes are visible to the underlying OS of the physical media and cannot be hidden from the administrator.
Another advantage is that OpenVZ can be rolled out on KVM and XEN, which allows you to achieve maximum VPS density on a physical server. This makes the cost of each individual virtualization so low that OpenVZ remains competitive despite its objective shortcomings and limitations.
XEN
A cross-platform solution included in the Linux kernel and distributed as part of the OS build. This is one of the factors that explains the high degree of popularity of the tool, but not the only one. Another important point is the support for paravirtualization. A paravirtual OS or PV is a modified copy of the main OS. It does not require emulation of the hard drive, which can significantly save resources, but imposes restrictions on the number of virtual copies. It should also be noted that not all operating systems support the creation of virtual copies.
If PV is not possible, XEN operates in full virtualization mode. In this case, support for additional extensions is required, which can lead to a decrease in performance. However, the OS accesses resources without the need for modification.
XEN is a time-tested solution. Users vote for it because of its high degree of stability and decent performance. Although it requires the allocation of a CPU core and sufficient RAM.
