Drivers for Change

Having the ability to network storage resources does not necessarily make it a good idea. Deploying technology for the sake of technology is not a sound business practice. So why have so many large- and medium-sized enterprises embraced storage networking? There are many reasons, but the primary drivers are the need for efficient management of storage resources and the need for competitive advantages that innovative storage solutions enable.

The volume of data generated each day by the typical modern corporation is greater than ever before. The growth of the Internet and e-commerce have increased the value of data, prompting businesses to store raw data longer, manipulate raw data in new ways, and store more versions of manipulated data. Recently enacted U.S. legislation mandated changes in the retention policies and procedures for financial records of public corporations listed on U.S. exchanges. U.S. companies that have operations in other countries also might be subject to various international regulations in those countries regarding data security and data privacy. Additional U.S. legislation mandated improved patient record-keeping for medical institutions. Recent world events have increased awareness of the need for all corporations, government agencies, and research and educational institutions to replicate data to remote sites for disaster protection. Many of the older enterprise-level applications that were written for optimal functionality at the expense of data life-cycle management cannot be rewritten cost effectively. These and other factors have resulted in storage capacities and growth rates that challenge the efficacy of direct attached storage (DAS) management.

Many corporations report that the cost of storage management is now greater than the cost of storage acquisition. Networking storage resources enables a new management paradigm. New protocols, products, and frameworks for the management of storage promise to reduce the cost of managing large-scale environments. The most prominent industry activity in this area is the Storage Management Initiative Specification (SMI-S) published by the Storage Networking Industry Association (SNIA). Vendor adoption of SMI-S is broad, and consumer interest is high.

Competition is fierce in global markets. The era of U.S. corporate downsizing epitomized the effect of that competition. Any competitive edge is welcome in such a business climate. Storage networks provide the potential to realize numerous competitive advantages such as the following:

• Increased throughput This allows input/output (I/O) sensitive applications to perform better.

• Improved flexibility Adds, moves, and changes are a fact of life in the operation of any computing or communication infrastructure. Storage networks allow storage administrators to make adds, moves, and changes more easily and with less downtime than otherwise possible in the DAS model.

• Higher scalability Storage networks allow greater numbers of servers and storage subsystems to be interconnected. This allows larger server clusters and web server farms by enabling horizontal expansion, and potentially reduces storage costs by enabling more servers to access shared storage hardware.

• Data mobility Storage networks increase the mobility of stored data for various purposes, such as migration to new hardware and replication to a secondary data center.

• LAN-free backups By deploying a storage area network (SAN), businesses can move network-based backup operations from the local-area network (LAN) to the SAN. This allows nightly operations such as batch processing, log transfers, and device discovery to run normally without competing against backup operations for LAN bandwidth. LAN-free backup was one of the original drivers for enterprises to adopt SAN technology.

• Server-free backups This is made possible by building intelligence into SAN switches and other SAN infrastructure devices to provide Small Computer System Interface (SCSI) EXTENDED COPY (XCOPY) functionality.

• Advanced volume management As virtualization technology migrates into SAN switches, it will enable robust heterogeneous volume management. Host and storage subsystem-based solutions exist today, but each has its limitations. Network-based virtualization promises to eliminate some of those limitations.

Another driver for change is the evolution of relevant standards. An understanding of the standards bodies that represent all aspects of storage functionality enables better under-standing of historical storage designs and limitations, and of future directions. In addition to the aforementioned SNIA, other standards bodies are important to storage networking. The American National Standards Institute (ANSI) oversees the activities of the InterNational Committee for Information Technology Standards (INCITS). Two subcommittees of the INCITS are responsible for standards that are central to understanding storage networks. The INCITS T10 subcommittee owns SCSI standards, and the INCITS T11 subcommittee owns Fibre Channel standards. The Internet Engineering Task Force (IETF) has recently emerged as another driving force in storage. The IETF created the IP storage working Group (IPS-WG), which owns all IP-based storage standards. Standards bodies are discussed in more detail in Chapter 2, "OSI Reference Model Versus Other Network Models."

Note

The ANSI X3 committee was known officially as the Accredited Standards Committee X3 from 1961 to 1996. The committee was renamed the INCITS in 1996.