Windows 2000 Performance Guide

Chapter 8. Disk Subsystem Performance

The storage subsystem of Windows 2000 is comprised of a variety of technologies including high-speed cache memory, main memory, disk storage, and removable tape storage, all integrated to form a hierarchy. At the top of the hierarchy are technologies that provide very quick access but at a high cost per byte; at the bottom are technologies that provide very low cost per byte but slower response. The purpose of building this hierarchy is for the overall subsystem to achieve the access time of the technologies at the top of the hierarchy but at an overall cost per byte that is fairly low. The typical access patterns generated by users combined with carefully selected algorithms allow a relatively small amount of memory for cache and main memory to absorb the majority of the requests, thereby providing on the average a very short access time.

Until recently, disks were the storage medium at the lowest layer in the storage hierarchy. Now tape devices of all kinds have been added to the hierarchy to further decrease the average cost per byte. Windows 2000 introduced a service called remote storage. This service transparently migrates files, under the control of configuration parameters established by the system administrator, from disk to tape storage devices. It is called remote storage to differentiate it from the storage of files on disks, which is considered local storage. Remote storage provides a uniform interface to a variety of tape storage ...