Algorithmic and Implementations of Storage Networks

Kay Salzwedel 1

HEINZ NIXDORF INSTITUTE
Paderborn, Germany

nkz@upb.de

Abstract:

The last storage hierachy in modern computers has to consists of durable, permanent storage devices that can keep the data over a long period of time. Obviously, this hierachy has the slowes access time and the larges capacity. Nowadays, magnetic hard disks are used to store the large amounts of data permanently. But even the ever growing capacity of disk drives cannot satisfy the ever growing demands for flexible and efficient storage systems. The simplest way to provide almost indefinite storage capacity is the use of disk drives in parallel. The underlying architecture of such a storage network can vary significantly. All we require is a number of storage devices (e.g. disk drives) that are connected and can be accessed from the outside.

In this paper we give an overview of existing techniques and implementations tackling the problems arising in such systems. Starting point will be an introduction of the problems originated in storage systems, like data distribution or data access balance. This leads directly to the definition and discussion of quality factors imposed on these networks. Using these factors will enable us to compare rather different systems even if a practical comparison is not possible. We describe the main ideas underlying the introduced systems and analyse them using the defined quality measures.