Offloading data: the emergence of outsourced storage networks
SPECIAL REPORTS / Optical Networking/WDM
WDM and optical-switching technologies will help providers take optical storage transport to the service level.
KANWAR J.S. CHADHA, Entrada Networks
Storage-area networks (SANs) have emerged as the preferred solution for companies grappling with surging data storage demands. In the near future, large carriers and smaller storage upstarts will offer enterprises storage transport and multiservice access solutions. Connecting SANs directly to the optical backbone will create an efficient and cost-effective optical storage transport solution that overcomes distance and protocol constraints.
By allowing storage to break free of the tethers of campus environments, storage service providers (SSPs) will make enterprise access to stored data geographically ubiquitous. SSPs also can offer scalability in the face of a data deluge and a host of disaster recovery options. Outsourcing storage will save emerging companies the massive capital expenditures required to network storage internally and enable them to focus on core competencies.
The next step toward networked storage services is to simplify the complex edge infrastructure of the metro network by integrating WDM, optical switching, and SAN transport technologies.
Data center professionals face the challenge of storing and accessing data from numerous sources ranging from enterprise resource planning applications and e-commerce to digitalized video, voice, and legacy data. As health care and other industries electronically automate records and processes to enhance services and reduce costs, storage capacity needs are soaring-not only in the financial sector, which is required by law to store and backup data-but across all industries.
Just as important as the storage of vast amounts of data is the value of transforming raw data into decision-enabling information through analytics and other data mining techniques. To fully exploit existing, constantly changing data sets, enterprises must make access to information easy, cost-effective, and ubiquitous.
Conventional SAN solutions come at a price, however. Enterprise users have limited access to valuable data and miss opportunities to make the best use of existing infrastructures. Users outside local and campus environments are frequently cut off from easy access to mission-critical information.
What's more, today's SANs fail to optimize expensive data-center infrastructure and hinder the development of data-center services such as storage outsourcing. Enterprises are therefore deprived of the economic benefits of consolidating storage capacity and of taking advantage of unused capacity available in multiple dispersed locations.
Fortunately, new approaches to extending SANs geographically and offloading storage traffic are afoot. One is a multiservice access approach that leverages the networking innovations taking place at the edge of MANs: WDM and optical-networking technologies.
The biggest bandwidth shortages today are in the metro network. Compared to the growth of bandwidth in WANs and LANs, the metro network has lagged considerably, only recently acquiring the 10-Mbit/sec capabilities available in the LAN well over 10 years ago. Bandwidth bottlenecks are now centered on the metro, where gigabit-per-second traffic grinds to a halt. That's an especially thorny problem for storage traffic, which explains the prevalence of Fibre Channel (1.06-Gbit/sec) SAN implementations. With its ability to guarantee the performance and reliability of SAN traffic, Fibre Channel is well established as the enterprise storage protocol of choice. But Fibre Channel can only take an enterprise so far in the quest to share data with branch offices, partners, and customers. Its reach is limited to 10 km, which is adequate for many campus environments but falls far short of meeting the data needs of geographically dispersed enterprises, even in a relatively small metro area.
To achieve a globally accessible SAN, storage transport must go beyond the distance limitations of Fibre Channel in a cost-effective and efficient manner. A key technology to accomplish that is an all-optical SAN switch that bridges the language barrier between Fibre Channel-based SAN traffic and carrier backbones. This task usually requires numerous translation devices like IP routers and director-level switches. This equipment can create bottlenecks in an already congested metro area where networks must handle fluctuating demand and disparate traffic types. An all-optical SAN switch can bridge the two worlds of Fibre Channel and carrier networks, achieving a common SAN to public backbone connection that enables native Fibre Channel over light transport.
If local SAN fabrics are to improve performance by extending across high-speed communications links to create a fully integrated global SAN, they must interface with the optical infrastructure being deployed in the metro today. To create a truly low-latency global SAN, optical networks must integrate at the device level to provide a seamless interface with carrier backbones. The result: Any remote SAN can be extended to any end user by creating direct high-bandwidth optical SAN-to-SAN connections that link disparate islands of SANs reliably and with low latency.
WDM increases fiber capacity by enabling wavelengths to travel down the same fiber independently, creating multiple channels that can support different bit rates and formats. It also reduces the need to lay new plant, which can cost several hundred thousand dollars per fiber-mile. Today, WDM can support up to 800 Gbits/sec of capacity. Future multiplexing innovations are expected to up the ante to 1.6 Tbits/sec.
The next step is a multiservice access SAN transport device with WDM capabilities. This architecture carries IP-based ATM and SONET traffic as well as storage-specific Fibre Channel, Escon, Ficon, and Gigabit Ethernet interconnections. WDM-enabled systems that support heterogeneous storage traffic can link enterprise data centers with remote locations, offsite storage facilities, disaster recovery, and data warehouse sites. The superiority of the multiservice access approach is clear: Interconnecting SAN islands with a high-bandwidth, high-reliability, low-latency network eliminates the need to ensure data protection and recovery through manual tape backup and vaulting (see Figure).
A multiservice access SAN transport platform with optical interfaces takes advantage of the bandwidth-boosting capabilities brought on by optical technologies. Optical-switching systems will allow network builders to support optical-layer restoration while creating new optical-layer services. Protocol- and bit-rate-transparent optical systems are highly scalable-unlike SONET/SDH-based network architectures designed to carry voice services-and feature much faster provisioning times.
Even as WDM decreases the cost of fiber, optical technologies are improving performance, flexibility, and manageability through wavelength switching and routing. The ability to transport and add/drop traffic within the all-optical domain will create the reliable global storage network that enterprises need. Highly redundant metro-optical systems will provide disaster recovery capabilities on par with SONET recoverability, ensuring the delivery of storage applications like backup in the event of system failures.
WDM and optical-networking technologies have created an abundance of bandwidth in long-haul networks. Metro networks may experience similar capacity excesses in the not-too-distant future.
Large and small carriers suffer from significant margin erosion as bandwidth costs drop precipitously. At the same time, they are under pressure to shore up revenues to support the sky-high network-building expenditures incurred over the last few years.
Service providers need a compelling service to fill their pipes, and storage services-first as transport, later as a hosted application-can fill carrier pipes and provide an important, in-demand service to enterprises worldwide. SSPs are in the fortunate position of meeting a real market need, a notable contrast to the hype-filled recent years characterized by attempts to sell "solutions" for which there were no real problems. The economic benefits of offloading storage are well documented.
Providers that today offer hosted IT and telecommunications services will likely want to host SANs. The business model associated with offering SAN services is greatly improved by the benefits of multiservice access all-optical SAN switching, which eliminates optical-electrical-optical translations.
Optical technology is attractive to carriers because it enables the deployment of new revenue-generating high-speed services in a more efficient, cost-effective, and flexible network environment. These networks are well suited for storage traffic because of their scalability, ability to transport storage traffic natively, and faster provisioning times.
As importantly, carriers can leverage their existing infrastructure to offer storage transport services. Service providers have already adopted WDM to support high-bandwidth services such as video, high-resolution graphics, and large-volume data processing. This traffic is typical of most storage traffic. The flexibility of optical networks enables carriers to add capacity where and when their customers need it. They can also provide the redundant capacity so necessary to storage traffic on a wavelength basis-a far better economic proposition than the standard route diversity achieved through redundant rings or point-to-point networks.
The corporate trend of focusing on core competencies and outsourcing IT requirements is gaining momentum worldwide. Outsourcing isn't just for small businesses, which rarely have the IT muscle to man their own servers or build their own storage depositories. Farming out technology needs-particularly labor- and training-intensive telecommunications infrastructure-is an appealing proposition for many enterprises.
As such, SSPs are aggressively positioning themselves to ride the wave of technology outsourcing. A rapid decline in enterprise bandwidth prices is also contributing to the positive prospects of SSPs. Rather than bemoan the falling prices of capacity, SSPs can use attractive rates to encourage enterprises to adopt a multiservice access approach to SAN transport.
Outsourced storage offers many advantages that enterprises will be hard-pressed to match in-house:
- Scalability. SSPs will manage enterprise disk capacity, mirror data sets, and back up systems from central storage locations. They can offer enhanced data availability as a result of their superior networks and other resources.
- Cost. Pay-per-use storage models will allow companies to pay for incremental increases in infrastructure needs, rather than purchase massive new systems as demands grow. In an era when highly qualified IT personnel are hard to find, outsourcing storage to experts offers real savings.
- Economies of scale. Some enterprises are already outsourcing the hosting of their Websites along with caching and network monitoring. Storage transport is the next logical candidate.
- Greater reliability. SSPs will be able to inter-network islands of SANs via efficient and reliable WAN technology, providing long-distance backup, disaster recovery, remote mirroring, and recovery over significant distances. Enterprises will obtain enhanced data availability, as SSPs handle the chore of replicating multihundred-gigabyte databases for 24/7 availability.
Outsourcing storage capabilities will be invaluable for those firms for which data is the business, such as banks and e-commerce companies. But others will find reason to take advantage of externally hosted storage as well when SSPs offer economical alternatives for enterprises with intermittent, event-driven storage needs; films in progress and biomedical research projects are two examples.
In the near term, the pace of storage outsourcing adoption is expected to be conservative. Enterprises accustomed to controlling every aspect of their data storage infrastructure-from proprietary storage networks to tape libraries-will not immediately entrust their valuable data to an SSP. Instead, the migration path will be incremental. Many enterprises are likely to first adopt multiservice access storage devices, which will allow them to benefit from the flexibility and business advantages of ubiquitously available stored data.
However, the trend is clearly toward greater acceptance of storage as a utility. Forrester Research reports that 48% of large companies will not consider outsourcing storage, which does not sound too promising until it's realized that just two years ago Forrester reported 100% would not outsource storage. In line with Forrester Research's findings, IDC expects the worldwide SSP market to reach $8 billion in 2004 from $11 million in 1999.
Large enterprises will likely invest in additional disaster recovery and data mirroring functionalities for existing infrastructure. The cost savings from better use of data-center resources and more bulletproof failover capabilities will justify storage transport and access solutions.
Initially, SSPs will attract industries that are especially data-dependent and have the most pressing need for remote storage applications. Vertical markets like health care, entertainment, and finance are already heavily targeted by SSPs.
Meanwhile, the general enterprise market will be served by both national carriers and storage-centric upstarts. Storage device vendors will partner with bandwidth providers and hosting centers; that's already occurring. A range of solutions will be offered to end users, in recognition that one size does not fit all in the storage world.
One thing is certain: WDM-based optical networking will enable SSPs to take storage beyond the enterprise and beyond the campus. Affordable storage services will proliferate as SSPs achieve even larger economies of scale. And enterprise customers will have the option to buy storage as needed-no more and no less.
In the not-too-distant future, the days when storage meant disks and tapes in the next room-not to mention trucking storage nightly to offsite vaults for safekeeping-will seem as antiquated as drawing water from the well in the backyard.
Dr. Kanwar J.S. Chadha is president and CEO of Entrada Networks (San Diego).