VPS的种类及超售问题

1.OpenVZ VPS:
特点:在几种VPS里面算是最便宜的(同等配置的情况下),但虚拟化不完全,系统中很多东西和他人共用(如iptables,相当不方便),也不可以配置VPN,基于OpenVZ的VPS可以被超售

2.XEN VPS:
特点:XEN目前是VPS领域最成熟的虚拟化技术,基于XEN的VPS支持多种VPN,各VPS系统之间是完全独立的,XEN 3.3及其后续版本支持Memory Overcommit,这种技术可以让主机提供商超售基于XEN技术的VPS

Memory overcommit provides the ability for the sum of the physical memory allocated to all active domains to exceed the total physical memory on the system.  For example, if your machine has 4GB of RAM and you want to run as many 1GB domains as possible, you can run at most three — because Xen and domain 0 require some physical memory also.  With the new memory overcommit feature in Xen 3.3, in some environments, you can run six or ten or even more.

原文链接:http://blog.xen.org/index.php/2008/08/27/xen-33-feature-memory-overcommit/

3.KVM VPS:
特点:KVM VPS的自由度是最大的,使用者可以随时重装系统,支持多种VPN,虚拟的是完全独立的系统