Comparison of virtualization technology with PV hvm

In xen, PV is semi-virtualized, and hvm is fully virtualized. PV can only be used in Linux kernel systems and is more efficient. hvm can Virtualize all common operating systems (windows can be used ), the theoretical efficiency is slightly lower than pv. In addition, hvm requires CPU virtualization command support (the CPU must enable intel VT or AMD-V). PV does not have this requirement.KVM is an emerging virtualization project. There are not many VPs vendors selling KVM, But it is said that KVM virtual technology is relatively powerful. Openvz is a fully-virtualized solution similar to Linux-vserver. Currently, there are many VPs service providers based on xen and openvz. This article briefly introduces and compares several common technologies openvz, xen, and KVM used by VPs, so that you can purchase your own VPs.

Openvz

Openvz Is A virtualization technology at the operating system level and a layer of applications on the underlying operating system, which means easy to understand and low-weight overhead. In general, it also means better performance. However, openvz is more flexible in configuration, giving black-hearted service providers the opportunity to lower their limits.

Advantages: This type is sold out now. The licensed memory is too large, the CPU is strong, and there are many sellers, and the comparison is strong. Cost-effective.

Disadvantage: Oversold, not oversold, resulting in a variety of stone disks, diamond disks. The associated CPU is also excessively divided, resulting in a performance appreciation of less than 1/10 as it indicates. Then there is the memory. Basically, openvz technology is not exclusive. It is shared. If there are more people, you will lose it. The biggest disadvantage of this technology is that the memory is directly used as a machine after it is down. There are also various inconveniences of opening VPN.

Xen

Xen is a semi-virtualization technology. It is not a real virtual machine, but is equivalent to running a kernel instance. It can freely load kernel modules, virtual memory, and Io, stable and predictable. The difference between xen PV and xen hvm is that PV only supports Linux, while hvm supports win system.

Advantages: Exclusive memory, although small, but guaranteed to be allocated. Some virtual technologies make it impossible to oversell the product. So even if the hen is too large, it rarely leads to a stone tray. Of course, this does not apply to chicks with Pt. In addition, even if the memory is low, the system does not respond for a period of time. Difficult to oversell!

Disadvantage: The memory is small, the hard disk is small, and the bandwidth is small (the above three points are compared with openvz at the same price ). Because I have not launched a sales spree, I can only drop these three basic configurations to make money. In addition, the suppliers are not doing well, and most of them are saying PV or hvm when talking about xen. In fact, PV performance is superior to hvm.

KVM

Advantages: Like xen, what is better than xen is that KVM is completely virtual, so regardless of the difference between PV and hvm, all KVM-type virtual technologies can be installed with various Linux releases and various win releases. Whether or not the vendor has stated on the home page that win is supported, as long as you have configured win to run, then you can install it, but it's just a method problem.

Disadvantage: Just because KVM can be installed with any type of operating system, win2003 is installed on even m machines. (After going up, all the CPUs and memory are used for hard disk Io, I don't understand what these people want to do ). The result is that all KVM neighbors have to look at the faces of their neighbors. In this case, if there are five or six machines under a node, I'm sorry, your hard disk is basically a stone disk.

Individuals prefer xen because it is an acceptable compromise between suppliers and customers. Openvz is so popular that KVM and others are looking at Rp. These two types are not suitable for webmasters who don't want to make any effort but just want to be the station.

Comparison of virtualization technology with PV hvm