一個有效的於分散式視訊伺服器環境下支援容錯處理之視訊資料擺放方法

Abstract

近來，視訊伺服器在隨選視訊系統中扮演一個很重要的角色。一般來說，一個好的視訊伺服器除了對客戶端提供播放要求之外，提供穩定的服務也是很重要的。在這篇論文中，我們提出一個有效的於分散式視訊伺服器環境下具有容錯處的視訊資料擺放方法，叫做Two Level Clustering (TLC)。此方法中又包括三種部份，即popularity-based replication, two level clustering, shift load scheduling. 經由popularity-based replication計算影片的份數，再用two level clustering將影片擺入磁碟中，最後用shift load的方法來作排程。它可提供伺服器容錯處理的能力以及改善磁碟群組間工作不均的問題，進而達到改善伺服器的穩定和輸出能力。透過我們的模擬環境，我們的方法的確較其他類似的方法有相當優異的效能，可以提供於此方面設計使用者良好的參考。詳細的設計原理與效能評估將在論文以後的章節中一一介紹。

Recently, the video server plays an important role in VOD or near VOD system. In general, a good video server can not only support playback operation, but also provide reliable service. In this thesis, we will propose an effective data placement scheme for supporting fault-tolerance in distributed video server environment, called Two Level Clustering (TLC) method. This method includes three parts, popularity-based replication, two level clustering, and shift load scheduling. Using popularity-based replication to calculate the number of replicas, we place the videos with two level clustering, and schedule with shift load scheduling policy. This method can support fault-tolerance ability and balance the load of the disks, thereby helping upgrade system performance crucial to archiving maximal server throughput and improve the system reliability. According to our preliminary performance evaluations, we have found that our method is superior than other schemes. The detailed information about design principles and performance evaluations will be described in the literature.