CLEC: Combination Locality Based Erasure Code for Permissioned Blockchain Storage

Building a new decentralized domain name system based on blockchain technology is helping to solve problems, such as load imbalance and over-dependence on the trust of the central node. However, in the existing blockchain storage system, the storage overhead is very high due to its full-replication data storage mechanism. The total storage consumption for each block is up to O(n) with n nodes. Erasure code applied to blockchains can significantly reduce the storage overhead, but also greatly lower the read performance. In this study, we propose a novel coding scheme for blockchain storage, Combination Locality based Erasure Code for Permissioned blockchain storage (CLEC). CLEC uses erasure code, parity locality, and topology locality in blockchain storage, greatly reducing reading latency and repair time. In CLEC, the storage consumption per block can be reduced to O(1), and the repair penalty can also be lowered to O(1). Experiments in an open-source permissioned blockchain Tendermint show that CLEC has a maximum repair speed of 6 times and a read speed of nearly 1.7 times with storage overhead of only 1.17 times compared to the current work, a great improvement in reading performance and repair performance with slightly increased storage overhead via implementation.