VPS (Virtual private server) [switch from Baidu]

System Selection

The common operating system on VPS is Linux (there are many distributions), Freebsd,windows server and so on. In general, the VPS operating system is not free to install, Linux series VPS can install multiple Linux distributions, but not installed Windows, the Windows Series VPs also cannot be modified Linux. This is the first thing to consider when buying, and decide which VPS to buy based on your needs.

I strongly recommend the use of Linux: Linux high efficiency, low hardware configuration requirements, high security, no need to run a graphical interface, you can freely streamline unnecessary functions, save the system resources used to run applications, rich and diverse network applications, Some software does not have a Windows version, or the Windows version is not effective, low cost.

　　Linux distribution Options : Linux has many different versions (distributions), most of which are Redhat series (for Redhat, CentOS, Fedora) and Debian series (represented as Debian, Ubuntu), Many of the major uses of the VPS are CentOS, Ubuntu, and other common retrofit versions, including Arch, openSUSE, and more. The difference between the different versions is not big, just see you know which, to which has the favor, with which. If you are new to the recommended use of CentOS or Ubuntu, especially Ubuntu, the response is pretty good; I'm personally inclined to use CentOS 6 because I'm more familiar with it.

Use a 32-bit or 64-bit operating system? Very responsible to tell you, do not hesitate to choose 32 people! Unless the following two scenarios: Your VPS memory is far more than 4G, or you want to run some software can only run under 64 bits. Choose 32 reasons: Run the same program, 32 bit memory is small, VPS use 32 people absolute majority, 64 and 32 places have not the same, there are difficult problems, 32 is easier to find information, find a friend to help solve.

Important parameters

When we buy, we should focus on the following technical parameters: virtualization technology, operating system, memory size, hard disk capacity, monthly traffic, number of independent IP, server location, ping value and so on.

Virtualization Technology

VPS is essentially virtual machines, are built on a certain degree of virtualization technology. The most current virtualization technologies are Xen, OpenVZ, Hyper-V, and VMware. Here's a rough look at the useful parts of the VPS to learn more about the extended reading "Xen, KVM, VMware, Hyper-V and other virtualization technology comparisons".

Where Hyper-V is Microsoft's own virtualization technology, it can only run on Windows, that is, the general purchase of a Windows system VPS, is likely to be hyper-V. Some of the smaller host chambers in VMware are running Windows or Linux, and friends who have used virtual machines should know about it.

The other two are virtualization technologies that mainly run Linux.

OpenVZ is an operating system-based virtualization technology that operates almost as efficiently as a real-machine (physical server). But don't be happy too early, the performance of the VPS is from the host, because there are many VPS on the host, each VPS can get the resources in fact not very high, specifically this depends on the host itself hardware performance, how many VPS run.

OpenVZ has several notable features: no swap partition swap (virtual memory), VPN that cannot run PPTP protocol, easy to be oversold.

(The new version of OpenVZ has been able to use swap in later versions of Linux 2.6, and also works well with PPTP protocol VPNs)

　　about oversold : Assuming that the host has 16G of memory, but out of 20 1G of memory VPs, are sold out, and these 20 VPS display 1G memory, which is oversold. In fact, OpenVZ is usually oversold even worse!

Xen, is a kind of technology called semi-virtual, performance than the real machine has lost, but virtual out of the system with the real machine similarity is very high, there is swap, can run PPTP VPN, not easy to sell. On Xen Linux, the kernel can be replaced or upgraded, and it is said that even a virtual machine environment can be virtual out of VPS (not seen, but even if successful, performance is extremely low, not practical).

Generally speaking, we all agree with the following statement:

The performance of purchasing Vps,xen with the same configuration is significantly better than OPENVZ. The main reason is the problem of oversold sales.

OpenVZ no swap, the memory isolated through the free command, some of which are in fact the swap of the host, just as the VPS as physical memory.

No non-oversold OpenVZ VPS.

512M of Xen, its memory performance is better than 1G OpenVZ VPS, or even far beyond.

OpenVZ the memory is exhausted, the system can only be restarted, because the remote SSH connection cannot be established. and Xen, and swap is available, usually not to restart.

It seems that Xen is almost over OpenVZ, the price, and Xen is much higher than OpenVZ. After all, the price of a penny.

For more information about Xen and OPENVZ, see the post-Extension reading "VPS Virtualization Technology-openvz vs. Xen".

KVM Virtualization Technology:

KVM (kernel-based virtual machine) is an open source system virtualization module that has been integrated into the major distributions of Linux since Linux 2.6.20. It is managed using Linux's own scheduler, so its core source code is few compared to Xen. KVM has become one of the mainstream VMM in academia today. KVM Virtualization requires hardware support (such as Intel VT Technology or AMD V technology). is hardware-based full virtualization. The early days of Xen were software-based simulations of para-virtualization, and the new version was full virtualization based on hardware support.

KVM technology has evolved from the initial concept to an enterprise IT infrastructure management system. Servers and devices located in multiple remote locations can be accessed directly from a single interface such as the KVM client management software.

Other related memory, hard disk, traffic, IP, ping value, etc.

memory size , hard disk capacity, monthly traffic, needless to say, is certainly bigger the better; Of course, the bigger the more expensive. Common memory typically in 256m-1g, HDD dozens of G, monthly traffic hundreds of G.

Independent IPs, usually one, are not enough to be purchased in addition. Some VPS abroad have an IP V6 address, but the IP V6 has not developed and popularized, the current practicality is not big.

The location of the server, it must be closer to the main user base, the distance from the near network delay small, fast speed; this is not absolute.

Ping Value , general testing network quality, we will ping, look at response time, packet loss rate, the smaller the better, but sometimes the ping value is very low, do not lose packets, but the speed is not fast. So the ping value is an important reference, but do not care too much, after all, VPS is not used to ping play.

VPS (Virtual private server) [switch from Baidu]