Distributed Schedule Management in the Tiger Video Fileserver

ACM SIGOPS Operating Systems Review 02/2004; 31(5). DOI: 10.1145/268998.266692
Source: CiteSeer


Tiger is a scalable, fault-tolerant video file server constructed from a collection of computers connected by a switched network. All content files are striped across all of the computers and disks in a Tiger system. In order to prevent conflicts for a particular resource between two viewers, Tiger schedules viewers so that they do not require access to the same resource at the same time. In the abstract, there is a single, global schedule that describes all of the viewers in the system. In practice, the schedule is distributed among all of the computers in the system, each of which has a possibly partially inconsistent view of a subset of the schedule. By using such a relaxed consistency model for the schedule, Tiger achieves scalability and fault tolerance while still providing the consistent, coordinated service required by viewers.

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    • "In contrast, a long cycle length makes it possible that more streaming sessions can be served concurrently, while startup latency becomes long and the quality of each streaming session is reduced. Most previous studies [8]–[10], [14], [16] that adopted cycle-based disk scheduling with fixed cycle length did not examine which cycle length was the most cost-effective. In this section, we present a method to find the most cost-effective cycle length. "
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    ABSTRACT: This paper discusses several practical issues related to the provision of video-on-demand (VOD) services, focusing on retrieval of video data from disk on the server. First, with regard to system design, the pros and cons of cycle-based scheduling algorithms for VOD servers are compared, and an adequate policy according to system configuration is presented. Second, we present a way to tune the cycle-based scheduling algorithm so that it maximizes profit. Third, a method to overcome the cons of cycle-based scheduling algorithms is proposed, and its cost is analyzed.
    IEICE Transactions on Communications 05/2005; 88-B(5):2156-2164. DOI:10.1093/ietcom/e88-b.5.2156 · 0.23 Impact Factor
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    • "There are numerous prototype file systems which are designed to handle multimedia data. Tiger Shark is a scalable, parallel file system designed to support interactive multimedia applications, particularly large-scale ones [7][6]. MMFS [4] improves interactive playback performance by supporting intelligent prefetching , state-based caching, prioritized real-time disk scheduling, and synchronized multi-stream retrieval. "
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    ABSTRACT: The EXT3NS is a scalable file system designed to handle video streaming workload in large-scale on-demand streaming services. It is based on a special H/W device, called Network-Storage card (NS card), which aims at accelerating streaming operation by shortening the data path from storage device to network interface. The design objective of EXT3NS is to minimize the delay and the delay variance of I/O request in the sequential workload on NS card. Metadata structure, file organization, metadata structure, unit of storage, etc. are elaborately tailored to achieve this objective. Further, EXT3NS provides the standard API's to read and write files in storage unit of NS card. The streaming server utilizes it to gain high disk I/O bandwidth, to avoid unnecessary memory copies on the data path from disk to network, and to alleviates CPU's burden by offloading parts of network protocol processing, The EXT3NS is a full functional file system based on the popular EXT3. The performance measurements on our prototype video server show obvious performance improvements. Specifically, we obtain better results from file system benchmark program, and obtain performance improvements in disk read and network transmission, which leads to overall streaming performance increase. Especially, the streaming server shows much less server's CPU utilization and less fluctuation of client bit rate, hence more reliable streaming service is possible.
    Proceedings of the 12th ACM International Conference on Multimedia, New York, NY, USA, October 10-16, 2004; 01/2004
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    • "Secondly, as nodes are added to a server, existing content must be redistributed. Many architectures also require that each sever node has an identical hardware configuration (Bolosky et al., 1997). Finally, the failure of any single node will lead to the loss of all streams, unless redundant data is stored (Wong and Lee, 1997). "
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    ABSTRACT: In a clustered multimedia server, by periodically evaluating client demand for each file and performing selective replica-tion of those files with the highest demand, the files can be dis-tributed among server nodes to achieve load balancing. This technique is referred to as dynamic replication. Several dy-namic replication policies have been proposed in the past, but to our knowledge, our work is the first to describe in detail the implementation of dynamic replication in a server cluster envi-ronment. In this paper, we describe the architecture of the Ham-merHead multimedia server cluster. HammerHead has been de-veloped as a cluster-aware layer that can exist on top of existing commodity multimedia servers – our prototype takes the form of a plug-in for the multimedia server in Microsoft Windows Server 2003 TM . Replicated state information is maintained us-ing the Ensemble group communication toolkit. We briefly de-scribe our own dynamic replication policy, Dynamic RePack-ing, and its implementation in the HammerHead server. Finally, we present early performance results from a prototype version of the HammerHead server.
    EUROMEDIA'2013, Plymouth, UK; 04/2003
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