Shardora: Scaling Blockchain Sharding Via 2D Parallelism

Document Type

Article

Publication Date

1-1-2026

Abstract

Blockchain sharding improves scalability but suffers from two critical performance bottlenecks during shard reconfiguration: TPS-degradation from ledger synchronization conflicts and Zero-TPS from transaction processing disruptions during key generation. This paper proposes Shardora, a blockchain sharding system that addresses these limitations through two-dimensional parallelism. First, Shardora introduces parallelized dual committee node shuffling that decouples ledger synchronization from transaction processing, eliminating TPS-degradation. A dynamic reputation model ensures security during shuffling. Second, Shardora implements pipelined key pre-generation to avoid Zero-TPS issue. Furthermore, its position-preserving incremental key generation minimizes resource conflicts, maintaining a continuously high TPS during key generation. We prove that Shardora offers theory-guaranteed security. We implement Shardora prototype and deploy it on Alibaba Cloud. Experimental results demonstrate that Shardora addresses the limitations by significantly reducing the overhead of both ledger synchronization and key generation, which shows 90%+ improvement over state-of-the-art sharding schemes. In addition, Shardora shows its superior performance in large-scale network, achieving 31911 TPS in LAN and 8729 TPS in WAN. The code of Shardora is publicly available on GitHub.

Publication Title

IEEE Transactions on Network Science and Engineering

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