Grid computing integrates abundant distributed resources into a single large-scale problem solving environment for parallel applications. However, the grid is a non-dedicated and dynamic computing environment. Grid applications consequently compete with each other for non-dedicated shared resources; moreover, shared resources are probably reclaimed by their owners according to administration policies, e.g. the scheduled maintenance. The job migration mechanisms which take the non-dedicated and dynamic natures of grids into consideration, therefore, become important for optimizing the application performance. The experiments of two job migration mechanisms, i.e. virtual machine migration and node reconfiguration by thread migration were presented in this study. We completed experiments on both LAN and WAN scenarios with a page-based grid-enabled DSM system, Teamster-G. The experimental results suggest the performance of virtual machine migration competes with node reconfiguration on equal terms; and further, they demonstrated the potential applications of virtual machine technique in the grid environment.