Storage Strategies for Fault-Tolerant Video Servers

Abstract

We consider the problem of providing high availability in cluster-based video servers. The cluster acts as a parallel processor that provides the aggregate I/O and network bandwidths of the component machines. In such an environment, the failure of one server may affect the availability of the video service or its quality. Existing approaches to this problem fall into two categories. On one hand there are RAID-like schemes that store error correcting code (ECC) in addition to the video data. Should a failure occur, the unavailable data can be computed on the fly using the ECC and the service continues at the same quality. In cluster-based systems, however, the video data are distributed over several servers and there is no convenient point to reconstruct the missing blocks except at the client. Relying on the client for this task is not desirable as it may not have the necessary buffering or processing capacity On the other hand, some argue that the system could just continue operation..