Abstract: As storage systems scale up，they consist of thousands of storage nodes.Multiple failures will occur frequently，which would induce a disaster because of data loss.How to design an efficient and reliable fault tolerance mechanism has become an issue that needs to be resolved urgently in disaster tolerance storage systems.Failure detection is a key technology to implement a system of disaster tolerance，but some simple failure detection algorithms can not satisfy the need of flexibility.In this paper a new concept of failure detector is provided，called weight failure detector.It can reflect the change of network state according to weight value changing.The experiment result can display that it can satisfy the need of flexibility.