Abstract: Many applications of Internet of Things (IoT) are performed by the continuous stream processing of the senor data and nodes replicas are required to guarantee system availability. However, the replicas backup and placement often bring the processing delay at run-time due to the consumption of resources such as memory and bandwidth. In this paper, a method is proposed as greedy fashion by the resources cost to place nodes replicas, which could tradeoff between the availability and overheads of the system. Moreover, in a practical system, the extensive experiments show that the availability of the proposed method can be provided in a more stable manner than the traditional random placement under the same conditions.