Recently, parallel computing is one of the main techniques to enhance computer performance. High performance computer can be applied to different fields, including commerce, national defense, and science. Numerical simulation is an important method that flourished science today. The simulation will fail if there is a intrusion during the simulation, so fault tolerance is an important issue. There are two main categories of fault tolerant techniques, 1) Automatic, and 2)Non-Automatic. Basic automatic fault tolerant techniques applied on clusters will be discussed, which includes coordinated, uncoordinated checkpoints and pessimistic, optimistic message logging. An automatic fault tolerant cluster under a scientific computational environment will be implemented with coordinated checkpoint. A storage backup strategy will also be implemented with a redundant array of inexpensive disks level five network file server.