Data popularity measurements in distributed systems: Survey and design directions

Distributed systems continue to be a promising area of research particularly in terms of providing efficient data access and maximum data availability for large-scale applications. For improving performances of distributed systems, several data replication strategies have been proposed to ensure reliability and data transfer speed as well as to offer the possibility to access the data efficiently from multiple locations. Data popularity is one of the most important parameters taken into consideration when designing data replication strategies. It assesses how much the data is requested by the sites of the system. In this paper, the importance of considering the data popularity parameter in replication management is highlighted. Different strategies are then identified and how they rely on the data popularity parameter is illustrated. Different calculation manners of data popularity are hence studied. This allows us to find out which factors are considered in order to assess data popularity. After classifying them into four categories, this work includes a critical discussion about each category. Some important directions for future work are then discussed towards possible solutions for a more effective data popularity assessment.