Broadcast Engineering talked to Joe French, senior VP at Masstech, about the use of disk storage versus a storage hierarchy, including data tape, to run a broadcast archive system.
“Tape has to be considered when looking at a storage strategy. It’s non-volatile (and low cost)” French said. Every three of four years, tape is allegedly on its last leg, but “it has been able to keep up with Moore’s Law, doubling in density every 18 months.” Tape provides opportunities for broadcasters, because a client may only use a piece of content every six months, he said. The tape can sit on a shelf or in a storage bin until it’s needed.
Many experts assert that tape formats become obsolete and files need constant copying to new media. But French pointed out that disk technology has a life of only a few years. “Most controllers can’t control a five-year old disk, so you are looking at updating disk technology every four or five years,” he said. “You can’t even buy replacement disks for five-year old arrays anymore.” The move from parallel SCSI and IDE to serially interfaced disks like SAS and SATA just confirms this. All this adds up to continuing migration of data from one medium to another, tape or disk.
“This is why I think that a broadcaster should have a hierarchical storage strategy, which divides their storage into mission-critical, high-performance storage, mid-tier storage at lower cost for interim, nearline storage and tape as a non-volatile backup” French said.
Masstech is not just in the business of moving data; the company supplies a complete file-based infrastructure, MassStore WAM (workflow-based asset management), including transcoding and low-resolution browse. The company’s focus is to link the file islands of post production and playout, enable the movement of content from production into the broadcast area without the costs associated with videotape, and manage all the different file formats.
Editing might be DNxHD, but broadcast file is long GOP MPEG. “Both these versions can be stored on tape, and a low-resolution proxy kept on disk for anyone who wants to take a look at it,” French said. Masstech can move the files, as well as transcode the file because Masstech has its own transcoding technology, he added.
The Masstech services such as data movers and transcoding can be exposed from their MassStore WAM Suite as an SOA interface to other applications including DAM/MAM. “We see that the most manual process in the broadcast chain is moving content from production into transmission,” French said. People are still moving tape around, and that adds to the operational expenditure. Anything that can reduce it will be attractive to a broadcaster, he said.
Data is traditionally written across a pool of tapes, with file copies written to different tapes. Many broadcasters group programs onto data tapes, so those tapes can be removed to an external archive. “We call this back-end grouping,” French said. This gives broadcasters extra flexibility and a strategy for disaster recovery, as well as a backup.
This year, more broadcast customers are moving to HD, which is increasing demand for tape storage. HD files are at least four times the size of SD files, so the capabilities of storage are constantly being pushed, in addition to bandwidth and transcoding time. “Broadcasters have to look more seriously at hierarchical storage” French said. And the more manual processes you can eliminate will lower operational expenditure, he added. Masstech sees layers of different storage technology contributing to lower capital costs, but retaining the performance needed to broadcast in HD. This flexibility provides backup and an archive within the file-based infrastructure.