Is the time right for optical storage?

Optical storage has languished on the periphery of enterprise storage, but new technologies with higher capacities and more competitive per-gigabyte prices are moving optical into the mainstream.

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Sometimes the stars and the planets in the technology universe align, and technology and user needs magically mesh. Optical storage, a technology that has spent a decade or more orbiting the far periphery of enterprise storage, is becoming more widely adopted. Higher capacities, improved performance and a more competitive price per gigabyte are propelling optical into more mainstream storage applications.

Optical has enjoyed modest success for specific archival tasks, particularly in the financial and healthcare industries where a physical write once, read many (WORM) record is required, but it remains a more expensive solution than tape. Although the lowest cost magnetic disk today remains more expensive than optical on the basis of the cost of the total storage system (hardware and software), prices for magnetic disk storage continue to drop (see Optical storage economics, this page). "There is a lot of price pressure from disk systems," says Wolfgang Schlichting, research director, removable storage at IDC, Framingham, MA.

Two recent developments are pressuring enterprise storage managers to look for the kind of long-term archival storage that optical provides. First, various regulatory mandates are forcing organizations to store more data and more types of data for longer periods, and to ensure that the data hasn't been altered. In addition, the data must be quickly accessible to auditors, regulators and lawyers. The second issue is the increasing recognition of the value of content. Rich media, such as graphics and images, needs to be preserved for the long term, yet remain easily accessible.

"Optical is getting much more attention than it got a few years ago. People are taking a second look because of mandates like Sarbanes-Oxley, HIPAA and Basel 2," says Schlichting. He expects that attention to translate into many more optical storage implementations. From 300 optical libraries sold in 2004 (5.25-inch magneto optical [MO] or Ultra Density Optical [UDO] format), IDC expects 5,000 libraries to be sold by 2008.

Plasmon, Englewood, CO, is the primary provider of UDO, which increases capacities by using an extremely focused blue laser to write and read data. "IT never purchased optical. Optical storage was always part of scanning and archives, and used for things like check images," says Dave DuPont, Plasmon's vice president of marketing. But the new demand for enterprise archival storage, combined with the more attractive economics of the latest optical technology, makes optical storage a viable alternative to tape at the low end and to inexpensive disk (ATA/SATA) at the high end.

Optical storage economics

UDO upstages MO
Until recently, the primary optical storage offering for this market was MO disk. MO uses a 5.25-inch disk read by a red laser. Current MO storage capacity is 9.1GB per disk. The disks can be loaded into multidrive jukeboxes that scale to multiple terabytes. "The problem with MO is that it's running out of steam," says Tom Sas, product manager for Hewlett-Packard (HP) Co.'s automated storage group in Loveland, CO. HP offers an MO-based system, but MO has reached its maximum capacity because of the size of the dot a red laser can manage. "We can't pack any more density on the disk, so MO will top out at 9.1GB," says Sas.

Picking up from there is the blue laser, which is the basis of several optical disk technologies. From an enterprise storage standpoint, the most promising is the UDO format. UDO uses a 5.25-inch double-sided disk that packs 15GB per side, or 30GB total. The roadmap for UDO currently stretches out to 60GB capacity, and then to 120GB capacity by 2007 or 2008. Because the disk form factor remains consistent from MO to UDO, organizations will be able to convert their existing MO robotics (jukeboxes) to handle UDO, although there will be no read/write compatibility. DVD is another optical 5.25-inch format that's non-proprietary.

MO disk technology will likely be around for another 10 years or more, but vendors have basically stopped trying to enhance it. "For some customers, MO is all they need. They will be able to continue using it, although it will slowly ramp down," says Sas.

UDO is no sooner ramping up than a potentially disruptive optical storage technology--holographic optical--has appeared. Holographic optical is being developed by InPhase Technologies, Longmont, CO. It uses roughly the same size disk as MO, but promises to put 300GB on each disk. Its roadmap calls for 800GB and then 1.6TB within a few years, says Liz Murphy, InPhase's vice president of marketing. Holographic drives will look like SCSI devices and provide random access like any disk technology. But Murphy doesn't expect the first commercial products to ship until the fourth quarter of 2006. Early adopters are expected to be media and entertainment companies that need high storage capacity for movies and high-definition TV.

Optical applications
At one point, optical storage was envisioned as the midtier of a hierarchical storage management strategy. It never panned out. "Optical would have required a usage change. The whole architecture was tuned to tape," says IDC's Schlichting. Instead, optical was adopted primarily for its WORM capabilities.

Information lifecycle management may yet revive interest in optical storage. "Certainly, optical is more viable now as EMC, Computer Associates, Veritas Software and others offer support for optical," Schlichting continues. IBM Corp., on the other hand, hasn't been active in optical storage for several years.

Optical storage shows up most often in the medical, financial and government sectors (see "Where optical works best," this page). It's also used in the media industry for the storage of digital content, according to IDC. The Dallas Morning News, for example, recently replaced a small DVD jukebox with a Plasmon UDO jukebox to permanently store photos shot by its photographers.

"We have the entire shoot if a question ever arises. We also go back and reuse our shots regularly," says Bob Mason, director of publishing systems at The Dallas Morning News. Now that it has the technology, the company is looking to expand its use of optical into areas like regulatory compliance and financial records.

Mason said that before purchasing the UDO jukebox, "we looked at tape because of its low TCO [total cost of ownership], but ruled it out due to its lack of permanence." UDO gave the newspaper what it wanted: WORM permanence, high reliability, a 50-year lifespan and a fast response to user searches. The newspaper looked at disk systems, but rejected them. "We had concerns about the amount of floor space required. Also, disk systems aren't perfect. You have to back them up. In the end, the total cost of ownership was too high," says Mason. The total cost of the UDO optical storage system came to approximately $150,000. This includes 638 disks, two jukeboxes for replication to a second data center, replication software and digital asset management software from The Software Construction Company, Alpharetta, GA.

DigiLink Inc., an Alexandria, VA, pre-press company, takes content provided by its customers and creates the type of electronic files needed for printing. In recent years, the firm has offered the actual printing as well. DigiLink takes customer content and initially stores it on a SAN. After the job has been completed, it sends the files to a 700-disk DVD jukebox for long-term archiving.

Before going optical, the company archived customer files on DLT tapes. "After four years of growth, we had over 100 DLT tapes," says Dave Whetzel, DigiLink's manager of technical operations. DigiLink also found it difficult to pull files from the tapes. With optical storage and Media Beacon digital asset management software, DigiLink and its customers can pull any file from the jukebox using a Web browser.

The firm opted for DVD over UDO, although UDO offers more capacity. "We didn't want something proprietary. DVD is a nice, open technology," Whetzel says. "I could [even] pull a disk and access it in a Mac," but he doesn't expect to.

Currently, each DVD holds 4.3GB of data. After one year of use, the company has filled 450 sides of DVD storage. The optical storage is accessed from the DigiLink's Windows servers through a StorageQuest Inc. appliance that acts as a NAS head for optical storage. The 700-disk jukebox can accommodate 1,400 sides. By the time DigiLink approaches capacity, "we expect DVD capacity to increase through the use of double layers," Whetzel says. Another option at that point is to plug in a second jukebox.

"It's just a SCSI connection out of the StorageQuest NAS head. We can daisy-chain more jukeboxes," he says.

Where optical works best

When optical isn't optimal
Despite the success organizations like DigiLink and The Dallas Morning News are having with optical and the emergence of new optical formats, optical storage still poses some problems for storage managers. To begin with, "you need some management tools in the storage system to work with the jukebox," says HP's Sas.

Another concern is the number of optical technologies and the frequent rate of change. Today, organizations can choose among MO, UDO and DVD. Coming soon will be greater density UDO and DVD, as well as holographic storage. And Sony Electronics Inc. is pushing another standard, Professional Disc for Data (PDD), which offers 23.3GB of rewritable capacity and a very attractive cost per gigabyte. Ostensibly for consumer usage, Sony has been signaling that it may direct it to the data storage market as well, and will introduce it this year to the broadcast industry. Faced with this confusing array of optical options, storage managers might just decide to continue to use tape until magnetic disk prices drop enough to become competitive with optical. In addition, optical requires bringing in yet another class of storage system.

Forces such as the continuing reduction in the cost of magnetic disk are working to undermine today's neatly aligned optical storage opportunity. But right now, optical storage has a window in which to establish a compelling value proposition and make itself an indispensable part of the enterprise storage infrastructure.

This was first published in June 2005

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