MTEC: A Multi-tier Blockchain Storage Framework Using Erasure Coding for IoT Application

Blockchain technology is widely used in the Internet of Things (IoT) with its decentralization, traceability, and tamper-resistant features. Unfortunately, the massive data volumes in IoT systems, combined with the prevalent full-replication strategy employed by conventional blockchain, exert considerable storage demands on IoT edge computing devices and present a formidable challenge for resource-constrained nodes to join blockchain networks. Although some existing solutions improve storage scalability by reducing the number of redundant copies, they still pose issues of high storage complexity and significant cross-tier query costs. In this paper, we first propose a multi-tier storage framework using erasure coding for blockchain, called MTEC, tailored for IoT scenarios with an exponentially decaying data access pattern. Specifically, MTEC employs Reed-Solomon(RS) coding to build a tiered blockchain storage framework. Each tier is equipped with an encoding scheme and threshold time to minimize storage overhead. To enhance query efficiency, we design a block pre-loading strategy and node collaborative query strategy. Finally, we implement a prototype of MTEC and compare it with baseline blockchain systems. Extensive experiments demonstrate that MTEC achieves a substantial 86.3% decrease in storage overhead compared to conventional full-replication blockchain solutions. It further outperforms state-of-the-art MLDC scheme by an additional 15.8% storage optimisation and reduces the cost of cross-tier to 7.35%.