Abstract: The performance of a disk cache subsystem is enhanced by dynamically sizing read requests based upon the current disk cache hit rate. Any data requested in the read request which is not the immediately requested data is located adjacent to the immediately requested data. Accordingly, the size of the read request depends upon at least one variable factor other than the size of the requested data. More specifically, the size of the read request is reduced as the disk cache hit rate declines, and the size of the read request is increased as the disk cache hit rate increases. Short-term and long-term disk cache hit rates are tracked. The short-term disk cache hit rate is used to determine the reduction in the size of the read request, and the long-term disk cache hit rate is used to determine the increase in the size of the read request.