Seamless Retrieval of Digital Continuous Media in Hierarchical Storage System
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Abstract:
In massive scale video streaming server, it is necessary to update the contents of the disk storage in regular fashion, e.g. daily, or weekly. This is particularly because the prohibitively huge amount of data maintained in the massive scale server cannot be stored solely on the secondary storage. Operation of retrieving the data blocks from the disk for streaming purpose bears tight timing constraints. Each video stream is assigned a certain amount of main memory buer to synchronize the asynchronous disk retrieval operation and synchronous playback operation. The disk write operation for content update may harm the QoS of the on-ging stream. Given that the temporal unavailability of the streaming service is not acceptable, we investigate the impact of writing the data blocks from the tape drive to the disk over on-going video playbacks. We propose to dedicate additional amount of memory buer to individual stream to mitigate the interference of non-real-time disk write operation(content update) with the ongoing video streaming. Based on the characteristics of the buer requirement of the continuous media streaming, we characterize the buer requirements for individual streams coexisting with content update operation. The main contribution of this work is to precisely indentify the amount of memory buer for individual streams to incorporate the content update operation. We visualize the impact of content update operation over buer space requirement via simulation based experiments.
