Emerging trends in file-based infrastructures

The history of business is filled with examples of once dominant corporations that failed or were slow to react to technology change and lost their market
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The history of business is filled with examples of once dominant corporations that failed or were slow to react to technology change and lost their market advantage. Despite many indicators to the contrary, the leading players in these industries viewed themselves in a traditional way while the market around them was undergoing a fundamental shift toward a new business model.

Today, the trend in the broadcast world is toward divergent, fragmented audiences that demand relevant content on a multitude of nontraditional platforms. Content owners must efficiently and quickly evolve with the times to ensure future stability of their business. A mandatory evolutionary step in the broadcast world is to move away from traditional videotape-based workflows toward file-based infrastructures.

File-based implementations affect every aspect of the broadcast workflow from capture and ingest through post production, storage, distribution and transmission. Add to these considerations the delivery of multiformat and multitarget content, and it becomes a very complex puzzle to solve. It is essential that the platform assembled provides the greatest flexibility to adapt to emerging file formats as well as new modes of content distribution and consumption without placing additional burden on the human component of the workflow.

To accommodate the advanced requirements, state-of-the-art file-based infrastructures are built with CSM systems at their foundation. This middleware solution provides the integration and abstraction layer allowing high-level user applications, such as automation and media asset management, to communicate and transparently control the complexities of the vast underlying storage infrastructure.

CSM vendors now offer unified integration to encoding platforms, transmission devices, newsroom systems and NLE platforms. They also provide key functionality, such as transcoding and automated content lifecycle management. (See Figure 1.)

After A/V content is encoded into a file, a properly designed CSM-based infrastructure allows that content to be stored, replicated, repurposed, transferred and reformatted across high-speed local or WANs. It does this without any human intervention and at many times faster than real time.

A fundamental portion of the CSM solution is the file-based storage infrastructure. These high-speed, mass storage devices are constantly evolving, largely driven by the IT industry. For the broadcaster, a range of technologies are now available to balance performance, reliability, scalability and cost. Typically these storage technologies include fast SAN disk arrays for content-intensive applications; less-expensive NAS disk arrays, robotic data tape and optical storage libraries; and offline storage of media ejected from the robotic library but still actively tracked by the CSM system.

Disk arrays are fast and offer random access to content, but they do have significant downsides when parameters, such as cost per terabyte, scalability, cost of redundancy and disaster recovery, are all taken into account. In data tape-based robotic systems, linear access and mechanical characteristics (robot arm movement, tape mount times, positioning time, etc.) dominate. When comparing disk arrays with data tape-based robotic systems, it is obvious that intelligent analysis is needed to choose and balance the correct storage technologies when designing an effective CSM infrastructure.

LTO-4

The evolution of data tape technology continues to advance at an amazing rate and can be considered mandatory for any future-proof CSM implementation. The latest and most compelling is the release of the fourth generation of LTO technology, LTO4, supported as an open standard by multiple manufacturers. These tape cartridges have 800GB uncompressed capacity providing enough storage capacity for nearly 40 hours of IMX50 SD content. This represents a significant cost and real-estate savings over the same amount of content stored on traditional videotape stock. Even more impressive is the fact that each LTO-4 drive is capable of sustaining 120MB/s transfers, which equates to the movement of one hour of IMX50 SD content in a little over three minutes. This is considerable performance improvement over videotape-based workflows. Savings are increased manyfold when the human factors regarding videotape-based workflows, such as physical transport, replication and quality assurance checks, are also factored into the equation.

In a robotic library, 10 LTO-4 drives can sustain well over 1GB/s of sustained throughput and can scale from there depending on the content workflow demands as services and distribution evolve. These speeds are impressive, but are based on the prerequisite that the CSM solution itself can effectively scale to meet these staggering performance demands.

Robotic systems and optical media

The mechanical overhead and linear nature of data tape robotic systems cannot be ignored. However, they also do not factor significantly into the overall system performance of a properly designed CSM infrastructure. By designing a solution that includes a careful balance of nearline spinning disk augmenting a backend mass data tape robotic library, amazing performance can be achieved.

Optical media technologies, such as holographic and Blu-ray, continue to advance, but not at the same rate as data tape technology. Although they do exhibit random access performance closer to hard drives than to linear data tapes, their density, cost per terabyte and transfer rates still pale in comparison. These technologies better serve acquisition and front-end newsroom editing operations rather than long-term storage goals at this point, but this may change as technology advances.

Mechanical performance characteristics for robotic, tape-based libraries can be methodically calculated to provide tangible performance metrics that can be used to factor into architectural choices. Figure 2 plots the end-to-end performance of different optical and data tape technologies in robotic library systems. Taken into account are robotic arm movement and media load times, media mount times, media seek times and drive transfer speeds for content encoded at IMX50 (or DV50) rates. The horizontal axis plots the duration of this file-based content in minutes (which directly maps to file size), while the vertical axis indicates the transfer performance as compared to real time.

For example, a plot point at the intersection of a 30-minute IMX50 asset on the horizontal axis and 6.00 on the vertical axis means the CSM system could transfer the content in a mere five minutes.

The main conclusion to draw from this multidimensional comparison is for short duration content (left side of the plot in Figure 2), the mechanical characteristics of the drive/library dominate the overall performance equation. As we move to larger duration items (toward the right side of the plot in Figure 2), drive throughput becomes the dominant factor.

Key to recognizing the significance of this graph is to appreciate that file-based content in any media-centric environment, whether in news or post production, will statistically span the entire horizontal axis and are not specifically limited to small files only. From an operational perspective, it is likely more acceptable to wait 94 seconds for a one-minute duration asset to be transferred using LTO-4 technology than it would be to wait nearly 50 minutes for a one-hour asset to transfer using Blu-ray technology. (See Table 1.)

While arguably insignificant in real-world implementations, the impact of the mechanical characteristics of data tape-based CSM solutions for short-form content can be further reduced by introducing a small amount of spinning nearline disk managed transparently by the CSM middleware. This nearline storage acts as a transfer cache for content moving in and out of the data tape robotic system and allows short-form content to persist on spinning disk for quick access while also protected on one or more data tapes within the robotic library.

Advanced CSM solutions allow content lifecycle policies to manage the migration of content dynamically tuning overall system performance to match creative workflow demands. As an added benefit, nearline disk also provides bandwidth balancing between fast data tape technologies such as LTO-4 and significantly slower broadcast devices, which typically run at less than half their speed, allowing optimization of overall CSM system performance.

The spinning disk technology evolution continues to be driven by the IT industry and now affords broadcasters commodity nearline disk-based solutions. One technology worth briefly mentioning is network attached grid-based storage. These are emerging as the most compelling, cost-effective and redundant spinning disk technologies for advanced CSM implementations, specifically targeted toward media-centric applications.

The CMS ideal

Of course, the underlying storage technologies represent only a portion of the overall CSM infrastructure architectural considerations necessary to design an effective system. The ideal CSM solution must offer broad and proven integration with different types of workflow or application-specific storage and remain open as needs and technologies evolve. Key to the design and architecture of an effective and future-proof CSM infrastructure are other factors, such as:

  • Application-specific storage technology support with differing QoS;
  • Seamless storage scalability and expansion;
  • Support for existing and emerging content and storage technologies;
  • Transparent storage technology migration;
  • System bandwidth extensibility as workflows and demands evolve;
  • Support for content reuse, analysis and other content-centric features; and
  • Focus on long-term content protection of valuable file-based assets.

State-of-the-art CSM solutions are capable of connecting independent media-centric workflows into an enterprise-wide system that unites all the storage within an organization and serves each workflow according to its specific needs. In the diverging world of content delivery, the CSM system provides the essential extensibility and flexibility to adapt to new industry conditions and deliver maximum value from an organization's valuable assets.

Brian Campanotti is chief technology officer for Front Porch Digital.

Table 1. Sample performance metrics for various drive/library technologies

IMX50/DV50 asset duration

1 minute 5 minutes 10 minutes 30 minutes 60 minutes Drive/library technology Blue-ray 1.1 minutes 4.2 minutes 8.1 minutes 23.7 minutes 47.2 minutes Holographic 0.6 minute 1.9 minutes 3.4 minutes 9.7 minutes 19.1 minutes SAIT-2 1.9 minutes 2.4 minutes 3.1 minutes 5.9 minutes 10.1 minutes LTO-4 1.6 minutes 1.8 minutes 2.0 minutes 3.1 minutes 4.6 minutes