# Ring-Overlap: A Storage Scaling Mechanism for Hyperledger Fabric
## 1 Introduction  
Blockchain technology arose from [PERSON]'s paper \"Bitcoin: A Peer-to-Peer Electronic Cash System\" [1], which describes blockchain as a decentralized distributed data ledger. It allows all nodes in the network to jointly own, manage, and supervise data through cryptographic methods, and the system operates without the control of any single node, thus providing characteristics such as unforgeability, untamperability, and traceability. Although blockchain technology improves data security and reliability, its current storage scalability is inadequate. The blockchain is shared by all nodes in the system, all nodes in the blockchain are equal, and each accounting node holds all transactions and blocks of the network [2]. As the network continues to expand and the data stored in the blockchain rises dramatically, the blockchain will face the problem of the storage limitation of single nodes. Therefore, the study of blockchain storage scalability is imminent, and a reasonable and effective storage strategy is essential.  
In recent years, sharding has emerged as an effective candidate technique for addressing the blockchain scalability problem [3]. It divides the network state into different sub-committees, each of which stores a portion of the data on each node, and the members of sub-committees can only process the set of transactions assigned to them [4, 5]. In other words, transactions are assigned to different shards so that different transactions can be processed in parallel between the shards [6].  
A blockchain platform can be classified into two types: public blockchain and consortium blockchain. Public blockchains are represented by Bitcoin and Ethereum, while the most widely used consortium blockchain is Hyperledger Fabric. Hyperledger Fabric differs from blockchains such as Ethereum or Bitcoin not only in terms of type, but also in terms of internal mechanisms [7]. Furthermore, it does not require expensive mining computation to submit transactions, which helps to build a scalable blockchain with shorter latency.  
Most blockchain storage scaling schemes are proposed for public blockchain, but public blockchain scaling suffers from the problem of not being able to support large-scalenetworks with high TPS, low latency, and security [8]. To address these problems, we propose ring-overlap, a storage scaling mechanism for consortium blockchain.  
The major contributions of the paper are the following:  
* The mechanism is to realize the storage scaling of the blockchain without increasing too much extra communication overhead;
* It tolerates the failure of some nodes without causing the loss of ledger data, which ensures the reliability of the system;
* It is compatible with the write and query mechanisms of Hyperledger Fabric, and only needs to add tiny extra maintenance mechanism.  
Finally, theoretical analysis and experiments of the proposed mechanism are given. The results show that a single node's storage space tends to _s/mn_, which greatly improves blockchain scalability. In addition, the security analysis of this mechanism demonstrates that if the number of failed nodes within a single cluster is less than \(s-1\) (\(s\) is the number of copies a single block within a single cluster), the mechanism can still guarantee the blockchain's data integrity.  
We note that a shorter conference version of this paper appeared in the literature [9]. Our original conference paper was only an initial idea of the ring-overlap mechanism and did not include experiments on system reliability or storage cost. This manuscript includes this section as well as additional analysis.  
The rest of this paper is organized as follows: the background and related works are reviewed in Section 2. Sections 3 and 4 introduce the problem description and scheme design. Then the analysis and simulation experiment are given in Sections 5 and 6. Finally, the paper is summarized and future work is outlined.