## 1 Introduction  
The birth of the distributed file system has been a milestone in file storage, effectively solving the problem of massive data management [1]. The distributed file system has many advantages such as cost savings, convenient management, good scalability, and strong reliability [2]. However, with continuous changes in the Internet environment, the functions and performance of the distributed file system in various application scenarios are also changing with each passing day. With the development of modern information science and technology, the era of big data has already quietly begun. Statistics show that my country's Internet penetration rate has reached 57.7%. The utilization rates of social applications such as WeChat Moments and Qzone are as high as 86.9% and 64.7%, respectively; 74.1% of netizens use short video applications such as Douyin and Kuaishou; mobile online shopping users have increased by 10.2% compared to the number of users at the end of 2017 [3]. When netizens use social applications, share short videos, or shop online, the amount of data generated in small files is vast, and it continues to grow rapidly. The Internet produces files such as pictures, texts, and short videos, which generates massive amounts of small file data. To better store and manage this massive data, it is necessary to design and develop a high-performance distributed file system suitable for small files, which is an urgent problem to be solved in today's Internet environment [4]. In the transmission of large files, network transmission delay is the main factor of the entire file transmission delay. On the contrary, in the new set of small files, the processing overhead of the file sending and receiving ends dominates the file transmission delay [5]. Specifically, processing overhead refers to buffer management, message replication in different memory spaces, and system interruption after message transmission is completed. In today's communication scenarios of the Internet, the information of small files such as messages, pictures, and short videos accounts for the vast majority of file transmissions. Therefore, most of the communication delay in the current distributed file system comes from the processing overhead of the message sender and receiver. The nodes of the existing distributed file system are mainly interconnected through Ethernet. In the traditional Ethernet communication method, multiple memory copies, interrupt handling, context switching, complex TCP/IP protocol processing, store-and-forward modes, and packet loss all lead to additional delays, resulting in large transmission delays and low system performance. Therefore, in the face of high-performance computing, big data analysis and surge I/O high concurrency, low latency applications, the existing TCP/IP hardware, software architecture, and high CPU consumption communication technology can no longer meet the needs of emerging applications. Under high-speed network conditions, the high overhead of host processing related to network I/O not only limits the bandwidth between network nodes but also reduces the performance and flexibility of network communication. Specifically, in the traditional TCP/IP protocol, the reason is mainly that message transmission needs to be passed through the kernel. This communication method causes high data movement and data replication overhead. At the same time, compared with the continuous improvement of processor speed, the development of the traditional Ethernet field is slightly lagging. It has gradually become a shortcoming of distributed file system performance [6]. Furthermore, it is difficult to support new network protocols and sending and receiving interfaces, which also have poor flexibility [7]. For this problem, RDMA network transport is a suitable solution. It reduces computing resource consumption while guaranteeing extremely low transmission latency.