Prospective for Global Storage Networks

Just how long will it be before the methods for moving media storage become synonymous with those of computer data storage in today’s global enterprises?
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Just how long will it be before the methods for moving media storage become synonymous with those of computer data storage in today’s global enterprises? We recognize that a principal differential in storing moving media as opposed to data storage for computer systems is based in part on how the two forms of storage evolved. The storage of moving media began with its own application specific storage medium – principally analog videotape.

Nonvolatile storage of computer data storage began with fixed magnetic core (rings), which were polarized to either a positive or negative polarity, and remained in a static state even after external power was removed. Over time, computer data storage moved from rigid polarized rings to flexible magnetic media in the form of tape and eventually spinning disk drives.

The storage of moving media endured its original forms (principally tape) for a relatively long time before it migrated to the disk domain. Yet the storage of computer data moved relatively quickly from magnetic rings to tape to rotating disk drives, where it still remains heavily entrenched in its most economical and widely accepted form factor.

GLOBAL COMMUNITY

The global community is now changing how data is stored. Now that moving media has migrated well beyond the analog domain (in lineal videotape form factor) to the nearly exclusive digital domain, the differences between computer data storage and moving media storage have become much narrower.

For more-permanent or archival storage of media (both data or moving images) a shift toward optical storage technologies is underway. Most can remember how commercial (and home) laser discs were a popular means to higher than VHS-quality recording and playback of moving images. Interactive laser disc presentations can now be seen as the precursor to today’s DVD (ROM and video).

Availability of DVD increases as does the ability to reproduce one’s own DVDs for data storage applications. The DVD may be rapidly encroaching on the CD-R (write once and write many) technologies that are today commonplace in computer stores and bundled computer packages for the home or business.

The explosion of requirements for data storage, of all kinds, is simply mind-boggling. And it is not confined to just business, industry and government. Sources have revealed that in the not-too-distant future the average citizen will posses upwards of a terabyte of stored information in various means. Where once we thought the 10 MB disk drive was enormous (the 1985 IBM PC-AT came with a 10 MB HDD), we now see 10 GB as the minimum requirement, just some 15 or so years later.

THIRST FOR STORAGE

Storage must move beyond the confines of spinning hard drives, removable tapes and optical disks if the thirst for data storage is to be quenched. We will still have need for protective backup and offline archive, permitting nonmagnetic discs and lineal tape systems to endure for years. Yet soon, over the next three to five years of technological development, the concepts of global storage networks will seek their own common denominators – changing the way we will view and apply data storage and use in a profound way.

Let’s briefly explore the various concepts in storage architecture that have matured in just the past three years or so.

Fibre Channel storage area networks (SANs) have become the storage networking choice for ensuring high availability and the ability to run data-intensive applications. SANs focus on separating large files, large block and streaming efforts from other congestive activities on the LAN. In turn, SANs mitigate many of the local area network bottlenecks in large area, close proximity applications (i.e., campuswide storage access). However, due to the limitations in Fibre Channel (with a peak distance of six miles), SANs are not particularly advantageous for remote servers or nonlocal computing efforts.

IP networks have become the most cost-effective, and preferred, of the networking solutions. IP, ideal for messaging, does not meet some of the more necessary demands for storage solutions. In particular, the QoS (quality of service), data-security and high-bandwidth demands for continuous duty storage access are hampered because the IP transport layer is not designed to manage the massive amounts of data that quantify storage applications.

Applications that interface SANs over long distances will generally require that data traffic be routed through servers that act as gateways to the wide area network. These servers require massive amounts of memory, and extremely high-speed or parallel processors making them cost-prohibitive for all but the most mission-critical applications where redundancy and online protective backup is a life safety essential.

SANS ALTERNATIVE

An alternative for the SANs/IP application is implementation of general-purpose servers that act as routers with a dedicated SAN over IP through switches that encapsulate Fibre Channel frames into packets for delivery of block-level data over wide area networks on a SAN-centric protocol. By dedicating storage area network routers and transport switches, a "SAN-fabric" can be connected over distance that creates a pseudo-SANlike appearance with lower latency and lower cost than the exclusively server-based solutions.

Optical switching and networking is standing in the wings ready to launch global storage networking to new dimensions. By reliability connecting isolated SANs islands over high-speed optical networks, the possibility of extending remote SANs to users is realized by the virtual creation of direct, high bandwidth, optically interfaced SANs – in similar concept to how network clouds are operated. Through the application of dense wavelength division multiplexing (DWDM), SAN switching and routing becomes a more viable metro-level solution and is viewed as the ideal transport for SANs traffic through the public network.

For the future, the conduits for global network storage might well be extended to many of the current applications that are bandwidth intensive and physical distance impaired. Some of the applications include: remote mirroring for disaster and security, storage outsourcing, whereby management and backup of data is handled by storage service providers (SSP); video on demand (VoD), whereby enterprises as well as consumers gain access to video media-based storage solutions; and data replication to reduce the dependence on overnight shipping of data tapes or transmission of data over costly WAN links that are slow to respond.

HOW LONG?

We posed the question at the beginning of this installment "how long will it be … ? The answers lie, in part, on the availability of and the real-time access to data. Both are key points to the successful implementation of data intensive applications – especially those that the content and programming industry such as over-the-air broadcast and cable-delivery will continue to depend upon.

We have seen computer networks and video servers evolve to become strategic assets. Still, we continue to struggle with the complications of the "last-mile" connection dilemma. The global storage network concepts give hope to bringing the edge of the network closer to the end user, and in turn may alleviate some of the issues associated with high-speed, wide area connectivity and storage asset management.