Innovative Approach to Data Placement in P2P Storage
A new method improves performance in peer-to-peer storage systems.
― 5 min read
Table of Contents
Peer-to-peer (P2P) storage systems are designed to use the combined storage capacity of individual users (peers) instead of relying on a central server. This approach helps in avoiding issues like a single point of failure, making these systems more reliable and scalable. With the growing amount of data we produce today, many new P2P storage solutions, like IPFS, Storj, and Swarm, have emerged.
One of the biggest challenges in P2P storage is how data is placed across different nodes or users. The method chosen for data placement directly affects performance, scalability, and reliability. Currently, many systems have issues such as uneven resource usage. For example, some nodes may be overloaded while others are underused, which can slow down the entire system.
Problems in Current Data Placement Methods
Imbalanced Resource Usage
Many P2P systems use a method called Kademlia-based DHT (Distributed Hash Table) for placing data. This method finds the nearest node based on certain calculations. While this approach works well for large networks, it doesn’t consider how well each node can handle the data. This can lead to busy nodes being overloaded, while other nodes that could handle extra data are left idle. This imbalance increases Latency, wastes storage, and decreases reliability.
Reduced Scalability
Some data placement methods require the system to maintain a global view of all nodes’ statuses. This means that the system has to always know where everything is stored, which adds complexity and can lower scalability since more nodes mean more information to manage. This method is often used in systems like Storj, which limits how well the system can grow.
A New Approach: Residual Performance-based Data Placement (RPDP)
To tackle these issues, a new method called Residual Performance-based Data Placement (RPDP) has been proposed. This method aims to balance the workload across all nodes based on their individual performance. The key idea is to select nodes for data storage according to their capacity to handle more data, which will help improve overall system latency.
What is Residual Performance?
Residual performance represents how much additional workload a node can handle, which is measured through two main factors: Throughput (the amount of data processed over time) and latency (the time it takes to respond to requests). By focusing on the nodes' available capacity, data can be placed in a way that improves response times and maintains balance within the network.
How RPDP Works
Monitoring Node Performance
For RPDP to work effectively, it requires knowledge of all nodes' performance in the system. Some nodes are designated as monitor nodes. Their role is to regularly collect performance metrics from other nodes in their group (clusters). Each monitor node keeps track of all nodes' throughput and latency, creating a dynamic scoreboard to rank performance.
Network Clustering for Efficiency
To reduce communication overhead, the whole P2P network can be divided into smaller groups or clusters. Each cluster has a monitor node that collects performance data from data nodes in its area. This organization minimizes the amount of information each node must share, thereby improving efficiency.
Data Placement Process
When data needs to be stored, the monitor node selects the best nodes based on their performance scores. This selection process considers the available storage space and the current workload of each node. The goal is to choose nodes that can handle the incoming data without causing delays.
Once the suitable nodes are chosen, the data is placed there, and a mapping is created that links the data to its storage location. This mapping enables easy retrieval later on without needing to know the complete structure of the network.
Data Retrieval with RPDP
Retrieving data stored in a P2P system using RPDP involves looking up the mapping first, which directs the request to the node holding the actual data. This two-step lookup process is designed to maintain efficiency while ensuring that the data can be accessed without needing a global view of the network.
Experimental Setup and Results
To see how well RPDP performs, experiments were performed comparing it to traditional Kademlia-based DHT methods. The simulations ran various tests to measure overall latency and how evenly the workload was distributed among nodes.
Latency Results
The experiments showed that RPDP achieved a lower overall latency compared to the traditional method. This means that data retrieval times were quicker, leading to a faster user experience. Specifically, RPDP improved overall latency by about 4.87% in the tests.
Variance in Latency
Another benefit observed was that the variance in latency was less with RPDP. This indicates that the workload among nodes was more balanced, providing consistent performance regardless of network conditions. In contrast, the Kademlia-based DHT method often caused larger discrepancies in response times due to imbalanced resource usage.
Scalability Observations
As the number of nodes in the network increased, both RPDP and Kademlia-based DHT systems showed similar trends in overall latency. However, RPDP consistently provided lower latency across all tested node numbers. This demonstrates that RPDP can efficiently scale without sacrificing performance.
Conclusion
The RPDP method offers a fresh alternative to traditional data placement strategies in P2P systems. By focusing on nodes' performance and balancing workloads accordingly, RPDP enhances system reliability, reduces latency, and improves scalability. While the method introduces slight complexities in data retrieval, the overall improvements in system performance make it a valuable approach in the evolving landscape of P2P storage solutions.
Future research can explore various aspects, such as fairness in data distribution and additional roles for nodes to support load balancing. These advancements have the potential to further refine P2P storage systems to meet the needs of an increasingly data-driven world.
Title: RPDP: An Efficient Data Placement based on Residual Performance for P2P Storage Systems
Abstract: Storage systems using Peer-to-Peer (P2P) architecture are an alternative to the traditional client-server systems. They offer better scalability and fault tolerance while at the same time eliminate the single point of failure. The nature of P2P storage systems (which consist of heterogeneous nodes) introduce however data placement challenges that create implementation trade-offs (e.g., between performance and scalability). Existing Kademlia-based DHT data placement method stores data at closest node, where the distance is measured by bit-wise XOR operation between data and a given node. This approach is highly scalable because it does not require global knowledge for placing data nor for the data retrieval. It does not however consider the heterogeneous performance of the nodes, which can result in imbalanced resource usage affecting the overall latency of the system. Other works implement criteria-based selection that addresses heterogeneity of nodes, however often cause subsequent data retrieval to require global knowledge of where the data stored. This paper introduces Residual Performance-based Data Placement (RPDP), a novel data placement method based on dynamic temporal residual performance of data nodes. RPDP places data to most appropriate selected nodes based on their throughput and latency with the aim to achieve lower overall latency by balancing data distribution with respect to the individual performance of nodes. RPDP relies on Kademlia-based DHT with modified data structure to allow data subsequently retrieved without the need of global knowledge. The experimental results indicate that RPDP reduces the overall latency of the baseline Kademlia-based P2P storage system (by 4.87%) and it also reduces the variance of latency among the nodes, with minimal impact to the data retrieval complexity.
Authors: Fitrio Pakana, Nasrin Sohrabi, Chenhao Xu, Zahir Tari, Hai Dong
Last Update: 2023-04-17 00:00:00
Language: English
Source URL: https://arxiv.org/abs/2304.08692
Source PDF: https://arxiv.org/pdf/2304.08692
Licence: https://creativecommons.org/licenses/by/4.0/
Changes: This summary was created with assistance from AI and may have inaccuracies. For accurate information, please refer to the original source documents linked here.
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