Global Storage Networks: Their Time Is Now.

Looking at the advances in IP networking, storage-oriented carrier networks, storage software and optical SAN transport technologies

As if one needed more proof of the tremendous impact of the global data explosion, researchers at the University of California are predicting that more data will be created in the next three years than in all of previous human history.

In a connected digital world, managing, accessing, copying, backing up, protecting, storing and moving information is more important than ever.

At the enterprise level, research firm International Data Corporation estimates that storage demand for an average Fortune 1000 company will grow an astonishing 650%, from 40 terabytes to 300 terabytes, over the next five years. E-commerce, both business-to-business and business-to-consumer, is leading the way to an environment where virtually all data is housed electronically. Sophisticated customer relationship management (CRM) applications rely on voluminous customer records. Next-generation scientific and technology breakthroughs, such as sequencing the human genome, hinge on the ability to quickly, securely and affordably access vast mountains of stored data. Even governments, traditionally the last large organizations to embrace new technologies, are slowly but surely migrating to all-electronic storage.

The data storage explosion is not confined to businesses and governments. As paper copies of medical, financial and legal records give way to digital documentation, personal storage will grow exponentially. In fact, some experts believe that in the near future, American citizens will, on average, possess a startling one terabyte of stored information. The latest Census calculated that the U.S. population now exceeds 281 million people. For the quantitatively inclined, that means that personal storage in the U.S. will soon require 281,000,000,000,000,000,000 bytes of data.

The Emergence Of SANs

Fibre Channel storage area networks (SANs) have become the storage networking choice for managing the data explosion, ensuring high availability of data and running data-intensive applications. SANs greatly alleviate local area network (LAN) congestion because they allow for campus-wide storage access and separate storage-oriented data, especially large block, streaming, and large file data, from the LAN.

However, since Fibre Channel SANs only extend about six miles, SAN data is inaccessible to remote servers and other non-local computing resources.

IT-savvy enterprises seek to locate resources where they are most needed and most economical and try to fully utilize existing capacity before adding additional resources. Indeed, most companies would welcome the opportunity to locate storage resources where space and labor are readily available and affordable. Today's SAN technologies often make these goals difficult--if not impossible--to achieve.

Key storage applications such as disk mirroring, backup and recovery are becoming mission-critical for ensuring ecommerce and enterprise continuity. Geographically dispersed companies incresingly seek to deploy these applications remotely over long distances. Moreover, the performance of many of these applications, and mirroring in particular, depend on low-latency networks. Constrained by SAN distance limitations and latency inducing networks, most companies find it difficult to achieve the benefits of cost-effective long distance storage solutions.

The next step in the evolution of storage networking is clear: global storage networks that provide access to stored data regardless of location. Global storage networks will greatly enhance data availability, power critical business and consumer applications and promote the nascent storage outsourcing movement.

Building a global storage network, however, presents more than a few challenges. It requires flexible, open SAN transport devices that connect currently isolated SAN islands over Internet Protocol (IP)-based networks, carrier networks optimized to carry storage data, software to manage the storage domain over long distances and the integration of advanced optical networking technologies.

SAN Over IP Requires Flexible, Open Solutions

IP networks, ideal for messaging, have emerged as the preferred and most cost-effective networking solution. However, they do not meet the quality of service, data security and high-bandwidth demands of storage applications. The IP transport layer that sends data packets and monitors delivery is not designed to effectively manage the massive quantities of data that storage applications utilize.

Current attempts to connect local SANs over distance usually require traffic to be routed through servers that interface to the wide area network (WAN). These topologies require expensive, high-end systems with extensive memory and extremely fast processors. This approach is cost-prohibitive and sacrifices flexibility--the key component to successful SAN over IP-network transport.

Instead of deploying a makeshift fix that is based on general-purpose servers acting as routers, dedicated SAN over IP switches and routers can lay the groundwork for a truly global storage network. These devices encapsulate or "wrap" Fibre Channel frames into IP packets to deliver block-level SAN data over WANs and metro area networks (MANs).

With dedicated SAN transport switches and routers, local SAN fabrics can be connected over long distances, making far away SANs appear "local" to remote users. In addition, this hardware results in lower latency and lower cost of ownership than server-based approaches.

As long distance SAN over IP becomes a reality, enterprises will need the flexibility to transport storage data over the best-fit WAN service, whether it is ATM, Gigabit Ethernet or OC-x. The choice of WAN transport service is dependent on the company's budget and the bandwidth required to support the application.

The Multi-Service Access Approach

The advantages of a flexible, multi-service approach are clear. First, WAN-link deployment decisions can be based on the needs of mission-critical applications. Second, it supports tighter cost control because bandwidth can be purchased based on need. Third, multiservice access ensures investment protection because incremental upgrades in connectivity can be ordered with minimal changes and disruptions to the overall system. Fourth, multiservice access is most likely the only efficient way to provide service across the enterprise given that all services are not available in all areas. Finally, multi-service access based on open protocols greatly enhances interoperability.

Flexibility, or protocol-neutrality, is also necessary on the SAN side of the transport equation. As competing standards evolve, many industry leaders are backing the development of open protocols being put forth by the major standards bodies. By contrast, relying on vendorspecific solutions yields a closed system, a common problem in the server-based approach and to early SAN-WAN routers. Closed systems lock IT managers into a specific vendor's solution, which may not service all of their needs effectively and offers no protection against technology obsolescence.

Public vs. Private Lines

The global storage network requires a connection that can effectively send large block and streaming data across long distances in accordance with strict performance and Quality of Service (QoS) characteristics.

To provide the proper cost/performance ratio to make global storage networking practical, network resources must deliver storage data effectively at the lowest possible cost. Some applications do not justify the cost of running over WAN infrastructure, especially dedicated WAN links, while other applications' performance might suffer over WAN infrastructure. Accordingly, alternativa cost/performance options need to be available.

The solution is to utilize the public network for handling storage data. Managed by common carriers, this SAN sensitive network would provide bandwidth on demand, offer deterministic delivery and cost-effectively provide appropriate performance and QoS capabilities. With this type of service, enterprises would have a high-speed connection to a shared network capable of carrying storage-oriented data at a much lower cost than dedicated lines.

Better Software

Storage management software must also evolve to meet the needs of a global storage architecture. Storage devices' performance and availability are altered when access is remote rather than' local. For global storage networks to operate efficiently, system software must recognize and differentiate remote from local resources and respond accordingly.

When storage resources are remote, WAN/MAN connections become gating factors. For example, some devices may be available intermittently over the WAN, while remaining constantly available locally.

To provide a dynamic picture of the global storage network, appliances and software that control the storage network must understand and adapt to the changes caused by remote access. Performance will suffer if, for example, the tape backup software treats a remotely accessible tape library as if it were a local Fibre Channel library. Storage domain controllers and storage management software, together with the application software, can solve this problem.

Advanced Optical Networking Technologies Come To The SAN

High-speed optical networks, especially in the metro region, are poised to propel the global storage network by connecting isolated SAN islands reliably and with low-latency. Optical technology--specifically SAN switching and routing devices and dense wavelength division multiplexing (DWDM)--will virtually extend any remote SAN to the end user by creating direct, big-bandwidth, optical SAN-to-SAN connections.

Achieving a low-latency global SAN requires the integration of optical switching and routing devices at the-network edge. Optical SAN transport enables SAN traffic to travel through communications networks without electronic-optical conversions. Such conversions cause network latency or traffic bottlenecks that slow the data transmission and stifle key applications such as disk mirroring. Bottlenecks become ever more pronounced when delivering massive terabyte-size storage files.

All-optical SAN transport devices have the potential to efficiently bridge the "language barrier" between Fibre Channel-based SAN traffic and the carrier backbone. Making the two worlds communicate currently requires a plethora of translation devices--IP routers and director-level switches--that add to network complexity and create application-killing bottlenecks.

Optical SAN switches and routers can eliminate Fibre Channel-to-IP-to-light conversions, creating a passive, protocol-transparent transport topology. A common SAN to public backbone language is achieved. These devices have the potential to deliver massive savings in equipment and, by eliminating electrical-optical conversions, will enable super-efficient native SAN over light transport.

Although SANs deliver data in large blocks, storage applications are often very sensitive to latency and thus require dedicated big-bandwidth data pipes--an option that most medium and small businesses find to be cost-prohibitive. Bandwidth-creating DWDM technology is changing this equation. By multiplying the number of channels that can be sent down a single fiber, DWDM is making optical storage transport a reality.

Passive optical systems, such as those found in many metro DWDM systems, are inherently transparent to data format and speeds, highly-scalable, and able to transport and add/drop traffic within the all-optical domain. In conjunction with optical SAN switching and routing, DWDM-based optical networking technology is the ideal conduit for seamlessly transporting SAN traffic through public communications networks--storage at the speed of light.

It's All About The Applications

The push for global storage networks is driven by the need for 24x7 data availability and a host of critical applications and business processes that demand remote real-time access to data.

Remote Mirroring. Increasingly a must for disaster recovery and e-commerce, remote disk mirroring duplicates data over unlimited distances in real time. Mirroring ensures data security and data access enterprise-wide.

Business Continuance. Global storage networks can ensure that precious data is protected when a natural disaster or major network disruption strikes. This is a critical issue in the age of e-commerce when an online brokerage can lose millions of dollars if confronted with a single hour of data unavailability. Linking SANs over the optical WAN allows for the copying of multi-hundred-gigabyte databases and guarantees 24x7 on-line availability.

Storage Outsourcing. Managing storage capacity and backing up systems require massive capital expenditures and an army of costly, hard-to-find storage professionals. The technologies behind global storage networks will help equip storage service providers (SSPs) to offer these and other storage services from centrally hosted sites. Rather than mirror data sets or implement complex software, companies can outsource the process to external or internal providers that handle backup, volume management, and vaulting.

Video on Demand (VoD). This fast emerging set of technologies will enable individuals and companies to select videos from a centrally hosted [source for real-time, on-demand viewing. VoD can be used for entertainment and education and also offer a wealth of business applications.

The biggest obstacles to a world with seamless implementation of VoD are last mile bottlenecks and lack of network infrastructure that can store, manage and transport massive-size video files. As broadband connectivity (xDSL, cable modems) becomes more commonplace, big bandwidth pathways will open to VoD hungry users. The lack of network infra structure that can handle the large amounts of data required by video remains a persistent obstacle to widespread VoD deployment. VoD will become a reality as SAN transport powered-global storage networks capable of storing, managing and transporting massive video files across optical backbones become commonplace.

Data Replication. Today, replicating large data sets over long distance requires constant shipping of tape and disk volumes via expensive overnight delivery services or transmitting data over slow and costly WAN links. As SANs are connected over a fiber backbone, their location becomes "transparent" to local users, enabling high-speed, high-volume data movement.

Supply Chain Integration. Effective, supply-chain integration means the ability to share forecasting, inventory, and logistics data with suppliers and customers. Global SAN fabrics will route data from partner to partner across the high-speed fiber backbone.

As computer networks have progressed, storage has steadily evolved from an afterthought to a strategic asset. In recent years, SANs have made great strides in ensuring data availability. The global storage network represents the next great leap forward as the world confronts unprecedented data storage growth.

IP and optical technologies, in tandem with advances in network services and systems software, are the keys to global storage networking. A new generation of IP routing devices that link isolated SANs over both public and private networks is needed. Carriers must evolve their networks to ensure secure, deterministic delivery of stored data. Storage management software and appliances must recognize remotely connected storage devices and manage them appropriately. Finally, optical SAN transport devices and DWDM must be deployed to facilitate low-latency storage applications across the optical WAN backbone.

As these technologies mature, remote storage applications such as disk mirroring and video-on-demand will become realities. Moreover, global SANs will create more cost-effective storage networks because they will allow economic location of storage and ensure higher utilization of resources. The technology behind global storage networks will power the SSP industry.

The global storage networked-enterprise will provide real-time access to all of its data regardless of location. In a world set to produce more data in 36 months than it did in the last several thousand years and whose people and businesses increasingly expect availability of their data around the world and around the clock, the global storage network is an idea whose time has come.

Dr. Kanwar J.S. Chadha is president & CEO of Entrada Networks (San Diego, CA).