Ken Freed /
06.25.2008 12:00AM
Disks Still Drive Video Storage
DENVER
Broadcasters wanting the most cutting-edge solutions for digital video storage can consider emerging solid state “flash” memory systems for professional use, but spinning disk drives and digital tape remain the most cost-effective solutions for most operations today.

“We keep a week’s worth of material online in a shared storage system,” said Victor Murphy, director of technology and operations at CBS affiliate WUSA-TV in Washington, D.C., “but we’re still archiving on tape, and I’m not sure when we’ll migrate the archive to online or nearline. With budgets being what they are, we have to be very careful about what we choose as solutions.”

WUSA recently moved from Avid’s Unity system to an Avid Interplay shared storage solution, which stores one week of programming, interstitials and spots. “It’s very comforting to have such a resilient and redundant system in house,” Murphy said. “So I’m sleeping a lot better at night now.”

Regarding solid state storage, Murphy said “Flash is a heck of a lot more expensive than a RAID array, especially with spinning hard drives getting cheaper and offering more capacity every day.”

Cost is the key factor in storage choices, said Karl Paulsen, CTO of AZCAR Technologies, a systems integrator in Canonsburg, Pa. “Higher costs means higher performance, such as for Fibre Channel disc storage with immediate access for multiple channels of ingest and playback.”

Paulsen noted that some storage solution vendors are focusing are internal applications and some on external, such as shared storage server networks for the main facility in contrast to small flash cards in field HD camcorders and trucks. “The main issue is getting all of the systems to operate together seamlessly within the context of operation automation,” he said.

Broadcasters should not expect universal standards for video storage any time soon, Paulson said. “The technologies are changing too fast, so there is no market advantage on developing standards that locks everyone into one way of doing things.”

HIGH PERFORMANCE, CONTINUOUS OPERATION

Four types of hard drives are being used for video storage, according to Andrew Warman, senior product manger for Nexio servers at Harris Broadcast in Northridge, Calif. These include SCSI, SAS, FC and SATA drives.

SCSI drives using the Ultra-2 standard get data rates up to 80 MBps with up to 15 devices connected to a single SCSI port in a daisy-chain. The latest Ultra-3 standard will handle data bursts from 80 MBps to 160 MBps.

SAS (Serial-attached SCSI) drives offer transfer rates from 3 Gbps up to 10 Gbps or more. SAS drives are compatible with SATA drives.

SATA (Serial Advanced Technology Attachment) drives are a major advance over the Parallel ATA drives in use for the past two decades on most computers. SATA drives start at 50 MBps and eventually will surpass 600 MBps.

Fibre Channel (FC) drives use a SCSI body with an FC interface to get data rates of up to 4 Gbps over optical fiber, coax cable or twisted pairs. The FC port allows for maximum stream connectivity of all these drives.

SCSI, SAS and FC drives are all designed for high performance and continuous operation. They can handle higher temperatures and more online connections because they are built with more robust components. Lower-cost SATA disk drives are chiefly designed for intermittent use by consumers, like ATA drives, but SATA drives can better handle multiple I/O streams and the connectors are sturdier.

“The biggest trend among broadcasters,” Warman said, “is switching to lower cost SATA drives because they offer the most storage capacity for the money. The SCSI drives have the highest reliability, and they are good for servers with multiple users, as are the enterprise-class SAS drives. If you need to share content instantly with multiple users across a SAN, FC and SAS drives are probably best.”

PILING ON

Broadcasters’ quick adoption of IT technologies is producing the shift to SATA drives, said Ross Summers, product manager for servers and digital news production at Thomson Grass Valley in Beaverton, Ore.

“A lot of the IT infrastructure in a facility can be leveraged for video storage,” Summers said. “We’re seeing more customers taking advantage of this internal bandwidth with Fibre Channel systems up to 50 terabytes or more.”

According to Johnathon Howard, director of broadcast media at Avid Technology in Tewksbury, Mass., their most popular solutions right now are standard Ethernet-based shared storage solutions, such as the Avid Unity ISIS (Infinitely Scalable Intelligent Storage) media network that can be linked to provide a thousand terabytes of storage, called a “petabyte.”

Creating clusters of storage systems is a related trend, said Geoff Stedman, senior vice president of products and marketing at Omneon Video Networks in Sunnyvale, Calif. “We’re seeing customers constructing interconnected storage nodes over fiber that allows them very good scalability and performance,” Stedman said. “Instead of server islands, such as one for production and another for master control, now all the users in the media facility can share access to the same content at once for streamlined workflows. You can write to a file once and not have to manually update multiple copies or backups on different servers.”

Improved access to archives is what most impresses Fred Fourcher, president and CEO of BitCentral a developer of broadcast news production systems in Irvine, Calif. “Archives no longer need to be offline on tape because of costs,” Fourcher said. “Based on interviews with the owners of the 70 Précis storage systems we’ve installed, the average station archives up to 300 hours of HD video per year, which is about five terabytes a year. The current price for SATA disk storage is $1,000 to $1,200 per terabyte, which means $5,000 to $6,000 per year, and the cost of drives is coming down fast. Even better, we’ve found that if a station has online or nearline archives, they access their archives much more often than with tape.”

Douglas Brooks, product manager for server and storage hardware at Apple Computers in Cupertino, Calif., agrees with this trend. “We’re going to see increased online delivery of stored video, as with the Final Cut Server,” Brooks said. “We’re moving toward an almost totally tapeless workflow, so ingest and editing and playback are integrated into one storage system. This will allow smaller operations to have the most advanced storage technologies.”


(click thumbnail)
SeaChange International introduced its Flash-memory solid state FML-200 storage system at the NAB Show in April.
ON DEMAND

Lower costs shape this prediction from Sherry Zhu, director of marketing for servers and storage at Acton, Mass.-based SeaChange International, which launched its first flash memory-based storage system at the NAB Show in April: “In five years, the costs of drives will be so cheap that broadcasters will be able to afford converting a large portion of their operations to flash memory, like cable is now doing for video on demand. This will become more critical when broadcasters launch VOD services of their own to take advantage of cable’s capacity for advanced services on the digital set-top boxes.”

What does Murphy expect to be doing at WUSA in five years? “Five years is a lifetime in this business,” he said. “I assume that we’ll have some sort of solid-state memory system in place for online, but I don’t know if the archive will be that way yet. The archive probably won’t be on hard drives any more. We may be using Blu-ray discs, but I honestly don’t know.”

Yet Murphy is certain about one thing. “Whatever system we choose will have to be file agnostic and vendor agnostic, able to handle a variety of files and formats, whether SD or HD or graphics or data. The hardest part is not the storage but keeping track of the materials. Anybody can put together a rack full of RAID drives, but knowing where to look for something in that rack and having it instantly accessible, that has to be our top priority.”


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