13.Network Storage Services

by Ian Pratt and Steve Hand (University of Cambridge, UK)

Link to the SOTA Chapter

Ongoing Research

Network storage interfaces can be classified by the amount of functionality provided by the device. High-level file interfaces such as NFS [NFS 1989] and CIFS [CIFS 1996] provide most of the functionality of file systems, and hence provide protection; low-level block-based interfaces like iSCSI [Satran] provide the functionality of disks, so it is much more flexible, any file or database system can use them; it is intermediate-level interfaces that have been the subject of more recent research. Such interfaces attempt to combine the safety of high-level interfaces with the flexibility of low-level ones. Object-based interfaces[Gibson 2000, Mesnier 2002] provide a middle ground between the two extremes, but they still provide such a high-level interface that devices must implement many functions which can benefit from application-specific policies. Ongoing work to correctly define the interfaces to network attached storage is taking place mainly in the industrial arena through the auspices of the National Storage Industry Consortium (NSIC). Commercial offerings of Storage Area Networks (SANs) also abound, with vendors such as IBM and HP shipping mature products.

Several current research efforts are building Internet-scale object storage systems by addressing the problem of distributing the functionality of an object store over a peer-to-peer network. This results in self-organising distributed object storage that provides high availability in the face of node failure or network partition. Examples of such systems include OceanStore [Kubiatowicz 2000], CFS [Dabek 2001], PAST [Rowstron 2001], Mnemosyne [Hand 2002] and XenoStore (nee Pasta [Moreton 2002]).

Future Directions

We can expect to see the commoditization of storage, and more precisely the integration of storage services into the network model. Some initial work here focuses on logistical networking, that is, considering storage and communication as tightly coupled problems and designing solutions accordingly. Other challenges for the future include building effective personal storage networks, enhancing data availability in times of network outage or partition, increasing information security, and raising the semantic level of access interfaces.

CaberNet Related Activities

The AutoMed project investigates the practical application of graph based database schema transformation, its use in automating global query processing and the application of heuristic and evolutionary computing techniques to schema improvement and global query optimisation for heterogeneous databases.


[CIFS 1996] CIFS: A Common Internet File System. Microsoft Interactive Developer Magazine. November 1996. available from http://www.microsoft.com/Mind/1196/CIFS.htm

[Dabek 2001] F. Dabek, M. Kaashoek, D. Karger, R. Morris, and I. Stoica. Wide-area cooperative storage with CFS. Proceedings of the 18th ACM Symposium on Operating Systems Principles (SOSP '01). Banff, Canada. October 2001.

[Gibson 2000] G. A. Gibson, and Rodney van Meter.Network Attached Storage Architecture. Communications of the ACM 43(11). November 2000 .

[Hand 2002] S. Hand, and T. Roscoe. Mnemosyne: Peer-to-Peer Steganographic Storage. Proceedings of the 1st International Workshop on Peer-to-Peer Systems. Boston, MA. March 2002.

[Kubiatowicz 2000] J. Kubiatowicz et al..OceanStore: An Architecture for Global-Scale Persistent Storage. Proceedings of the Ninth international Conference on Architectural Support for Programming Languages and Operating Systems (ASPLOS 2000). November 2000.

[Mesnier 2002] M. Mesnier.The Rebirth of Object-Based Storage. Intel Developer Forum Presentation. January 2002. available from ftp://download.intel.com/labs/storage/download/rebirthOSD.pdf.

[Moreton 2002] T. D. Moreton, I. A. Pratt and T. L. Harris.Storage, Mutability and Naming in Pasta. Proceedings of the International Workshop on Peer-to-Peer Computing at Networking 2002. Pisa, Italy. May 2002.

[NFS 1989] NFS: Network File System Protocol Specification. RFC 1094. Sun Microsystems, Inc.. Menlo Park, CA. 1989.

[Rowstron 2001] A. Rowstron, and P. Druschel.Storage Management and Caching in PAST, a Large Scale Persistent Peer-to-peer Storage Utility. Proceedings of the 18th ACM Symposium on Operating Systems Principles (SOSP '01). Banff, Canada. October 2001.

[Satran 2002] J. Satran, K. Meth, C. Sapuntzakis, M. Chadalapaka and E. Zeidner.iSCSI. Internet draft available at http://www.ietf.org/internet-drafts/draft-ietf-ips-iscsi-18.txt


Maintained by Rogério de Lemos (r.delemos@ukc.ac.uk)
Last updated 4 November, 2002