A Scalable Storage Framework for IoT-Based Blockchain Systems

Blockchain has been the foundation of Web 3.0 because it creates trust through decentralized data availability and tamper resistance. However, storage scalability is a bottleneck due to the explosive growth of blockchain data, posing a challenge for devices with limited computing and storage resources, such as IoT devices, to maintain a complete copy of the blockchain data. In this article, we propose a scalable storage framework for IoT-based blockchain that utilizes collaborative storage to lighten the storage burden on blockchain nodes. Nodes on the blockchain are grouped, and the nodes in each group pool their resources to maintain a complete copy of blockchain data. We formulate the block storage problem based on node groups to minimize communication cost, storage cost, and query cost while considering node capacity and block redundancy. We break down the problem into two separate subproblems: node group creation and block allocation. The former involves dividing blockchain nodes into groups, while the latter involves allocating blocks to nodes within a group. We demonstrate the NP-hardness of the subproblems and propose heuristic algorithms. We conducted thorough experiments using both synthetic data and the blockchain prototype system. The experimental results confirm the efficiency of the proposed framework.