Apparatus and method for data storage and retrieval using bandwidth allocation

摘要

An apparatus and method is provided for allocating a data file across a plurality of media servers in a network, wherein each media server has associated therewith one or more levels of I/O devices organized in a hierarchical manner. An attempt is made to allocate the storage of data across the I/O devices in such a way that the bandwidth imposed on the devices when the data file is sequentially accessed will be balanced, and optimum use of I/O bandwidths at all points in the system is achieved. This balancing can be done by incorporating knowledge regarding various bottlenecks in the system into the decisionmaking process required for distributing the data blocks. The method and apparatus further allows bandwidths to be allocated to various clients in the system at the time a data file is opened. Various checks are provided at the time a data file is accessed to ensure that the data rates actually imposed by the requesting client do not exceed that requested by the client at the time the data file was opened. The invention allows for much more efficient use of the I/O resources in a system and ensures that a given configuration will be able to support client requests.