Memory sharing management on virtual private server

Data center required to guarantee high availability of service to users. Recently, most data center use virtualization technologies to provides high availibility service. The virtualization technology allow a physical server to be virtualized into multiple virtual servers. This virtual server is logically working separately although physically located on the same hardware. When several virtual servers are created and they have heavy workload, server with limited resources must able to manage the use of resource among vitual server. We propose a memory resource sharing among virtual machine in order to achieve high availibility services. A virtual server that has an overload can get memory resources from another virtual server that has less workload and it has memory unused. In addition, the virtual server can also use the Hardware Node RAM unused in case that all virtual servers have heavy workload and experience memory exhaust. Thus, high availibility services can be achieved.