Hybrid storage architecture for video on demand server

Abstract

Large-scale video on demand (VOD) services use hard disk drives (HDDs) to store large video files. However, VOD performance is limited by the relatively low bandwidth access and high HDD latency access, which increase dramatically when a VOD server receives a large number of simultaneous requests. By contrast, flash-based solid-state drives (SSDs) are an attractive alternative because these ensure fast access to an intensive reading system such as VOD. A flash-based SSD only stores popular videos to provide fast access for read-intensive workloads. Unfortunately, replacing the entire HDD with SSD is costly because of its high cost per gigabyte. Therefore, hybrid HDD storage and the small capacity of a flash-based SSD can provide high but cost-effective performance in relation to the storage subsystem of a VOD server. The main goal is to improve the performance of the VOD server by maximizing the number of concurrent user requests and minimizing startup latency in a cost-effective way. Experimental results show that the hybrid HDD storage with flash-based SSD provides better performance than the HDD-based system because it can reduce the average response time for a large-scale VOD storage server by approximately 52.44%.