| RAID, Fibre Channel reach optical storage |
| New technologies may open up new
application areas, but user acceptance is expected to be slow. |
|
| By Zachary Shess
- (For Original Article, Click Here) |
|
| For the past
several years, optical library/jukebox vendors in essence have been preaching to the choir
of niche markets. Unit shipments continue to decline as fewer traditional customers in
document imaging, medical, and video applications purchase optical libraries to address
their specialized needs. |
|
| And the
relegation of optical devices to secondary storage roles in IT environments has caused
vendor defections. For example, in the last 18 months, Sony exited the magneto-optical
(MO) library market and Cygnet Storage Solutions sold off its write-once read-many (WORM)
optical business to Plasmon. |
|
| However, recent technology
developments in optical storage may finally address some of its deficiencies, while
satisfying expanding application and capacity requirements generated by the gigantic
amount of digitized audio/video files and Web-based content. |
|
| One new
technology is optical RAID. At this spring's NAB and AIIM shows,
DVD-RAM library vendors
Asaca Shibasoku Corp. of America, Cygnet Storage Solutions, and Disc Inc. demonstrated
optical RAID capabilities based on controllers from Ultera Systems. In addition, Maxoptix
has demonstrated its MaxRAID MO towers with the Ultera Striper 3 series controllers. These
demonstrations marked the first time that optical storage devices have been able to
leverage the increased performance and fault-tolerance benefits of RAID technology. |
|
| Another hope for
an optical comeback rests on the possibility that libraries may soon be deployed in
storage area networks (SANs) via Fibre Channel attachments. So far, SAN-based storage and
backup/archival devices have consisted primarily of disk arrays and tape libraries.
However, Hewlett-Packard in April announced that its HP SureStore E MO libraries support
point-to-point Fibre Channel connectivity. |
|
| Optical storage
vendors readily admit that libraries have suffered from relatively slow transfer rates and
a lack of software to span files across multiple discs or libraries, a characteristic of
RAID. Both of these drawbacks have hampered widespread adoption in mainstream data
centers. |
|
| "You were
limited to the file size that could fit on one side of the media. So to accommodate
streaming video, for example, we needed a larger file capacity that could span across
disks," says Chris Stone, Asaca's U.S. director of sales and marketing. |
|
| Optical RAID
|
| Armed with
traditional RAID benefits, optical library vendors now believe their devices can reach new
markets. Similar to traditional hard disk arrays, striping data across
DVD-RAM or MO
drives in a single library, or across up to five libraries, improves data transfer rates
because the drive group or libraries appear as a single entity to the host server (see
Figure 1). By grouping a four-drive RAID set with a parity spare, transfer rates can be
increased up to 4x. The Ultera Striper 3 controllers offer support for RAID-0, RAID-1, or
RAID-3 configurations. |
|
| The Ultera
controller can also operate with five libraries as though they were a single library
directly attached to the server (see Figure 2). This configuration is sometimes referred
to as a redundant array of independent libraries (RAIL). |
|
| To increase
fault tolerance, especially with larger capacities, RAID-1 mirroring can provide redundant
array protection. Five copies of data can be created simultaneously. |
|
| The optical library array
and controllers identify which piece of media corresponds with the proper RAID set, and
write data from removed-and then replaced-media back in the correct RAID configuration. |
|
| "A
traditional RAID controller does not expect a disk to get up and walk away," says
Fred Bedard, Ultera's vice president of sales and marketing. "However, when you eject
optical media and take the RAID set out, the controller now needs to know that media can
be removed. When the media is replaced, the data needs to be back in the same order." |
|
| New
applications |
| Optical RAID
also helps increase library capacities, which may open up new applications. With RAID sets
able to group drives and/or libraries, libraries can be logically grouped together to
appear as a multi-terabyte system. |
|
| "Users are
considering optical RAID for large applications with high volumes of data and large data
blocks, such as video streaming and Internet applications with high-resolution
graphics," says Wayne Augsburger, vice president of sales and marketing at Cygnet.
"With optical RAID, you have a good transfer rate and essentially much larger media
capacity because you're looking at four times the capacity." |
|
| Industry
analysts, including Data-quest's Mary Craig, also see the potential for optical storage
being used in backup applications. However, Craig does not anticipate overnight adoption.
"I think it's going to take some education, and some users will want to see it proven
first. Traditionally, backup is done with tape, so it's going to take some time to get
administrators to take optical seriously for backup applications. RAID technology provides
about the only chance that optical can be used for backup," Craig says. |
|
| Fibre Channel
connectivity* While RAID-equipped optical libraries will soon make their way into customer
sites, widespread connectivity via Fibre Channel to SANs may be a couple years away.
Hewlett-Packard recently announced Fibre Channel attachment for its SureStore E MO
libraries. However, HP will initially offer only point-to-point connection via a
SCSI-to-Fibre Channel router. Fibre Channel connections for arbitrated loop and switched
fabric topologies are due later this year. |
|
| HP officials and
industry analysts acknowledge that early demand will not be high, but both expect some
interest for specialized applications that require longer connection distances. Like
libraries equipped with optical RAID, Fibre Channel connectivity is not expected to
generate widespread interest until optical devices are considered to be viable backup
solutions for SAN environments. For that to happen, arbitrated loop and switched-fabric
support is necessary. |
|
| "To just
provide a jukebox with a Fibre Channel connection does not solve anyone's problems,"
says Mike Peebles, HP's MO product manager. "When we start having multiple hosts that
have the ability to access a common jukebox in SAN environment, that's when the benefits
of shared resources will be worth the investment." |
|
| The industry's
other MO vendor, Maxoptix, currently does not have specific plans to connect its libraries
or towers to Fibre Channel. David Kalstrom, vice president of marketing at
Maxoptix, says
the company at this time is focusing primarily on delivering initial shipments of its
Optical Super Density drives and media later this year. |
|
| Analysts and
vendors agree that RAID technology and Fibre Channel connectivity are not magic elixirs
that will quickly cure the woes of the high-end optical storage market. However, both
technologies present some potential for optical libraries to address problems across a
broader scope of applications. |
|
|
|
Medical industry embraces DVD
Medical software vendor uses DVD-R libraries in its turnkey cardiology imaging network.
By Zachary Shess |
|
| DVD proponents
have touted the technology's ability to deliver high-capacity, random file access with
vastly improved image resolution. While technology benefits always seem to be translated
into cost and time savings, one software company is coupling its technology with DVD to
help heart patients experience real life savings. |
|
| Storage
administrators at 2,300 cardiology labs nationwide face rapidly increasing capacity and
business-critical requirements for secure, reliable file access. They also have concerns
about costs and the ability to manage data across divergent file systems. |
|
| Cardiologists
have recently benefited from a number of technological advances, such as the ability to
diagnose heart problems by inserting miniature 35mm cameras into patients' arteries.
However, once these images are placed on film, new management challenges emerge. While the
Digital Imaging and Communication in Medicine (DICOM) standard has provided medical
imaging device manufacturers with an interchange method for managing various types of
image files, no standard has been established for how to best store these images and make
them ready for easy, fast access to medical staff. |
|
| While DVD
technology has yet to gain widespread adoption, its high resolution has won over users in
some applications, none more critical than helping diagnose heart conditions. In addition
to providing clearer images, DVD helps cardiologists retrieve data more quickly than other
optical technologies. In addition, with DVD's increased capacities, more data can be kept
on the network. |
|
| Heartlab Inc.,
a Westerly, RI-based software developer and systems integrator, provides a turnkey system
for cardiology labs that eliminates film and replaces it with higher-resolution digital
images. On the software side, the DICOMview Cardiac Network, installed in more than 600
labs worldwide, includes proprietary Windows NT-based cardiac imaging software that
digitizes a patient's cardiac test results. Once the DICOMview Angiographic Review
software chronicles a patient's condition, DICOMwriter software facilitates file access
from the storage devices. |
|
| The suites are
bundled with a network of Dell servers and workstations equipped with special
high-resolution monitors. By networking devices over Gigabit Ethernet or ATM, medical
staff can view patients' results right from the emergency room, saving critical time. |
|
| The servers and
workstations access stored files via SCSI from a FlexLibrary DRM-7000 recordable DVD
(DVD-R) library from Pioneer New Media Technologies. The FlexLibrary series holds up to
670 DVDs, or 3.2TB-enough capacity to store approximately 14,000 patient records. |
|
| From the
company's inception in 1994 up until last year, Heartlab Inc. archived data on DLT tape
libraries. When Heartlab president Robert Petrocelli was approached in early 1999 to
consider DVD, he was skeptical. However, after a one-year beta test pitting
DVD-R against
DLT tape, as well as other optical technologies, Petrocelli changed his mind and began
installing DVD-R libraries in the DICOMview Cardiac Network. |
|
| On average,
cardiology labs spend about $58 on film for each patient. Petrocelli claims that by using
DVD-R media, its cardiac system should cost a lab less than $30 per case. Additionally,
Petrocelli says the cost of providing 3TB of DLT storage is about 30% higher than
DVD-R. |
|
| Heartlab also
found value in DVD-R's random access capabilities and retrieval speed. For example,
archival speeds went from about five minutes to less than one minute. Engineers also
tested magneto-optical and DVD-RAM, but found the read/write performance to be slower than
DVD-R. |
|
| However, the
ultimate value of DVD-R as part of a specialized cardiac network is its ability to provide
doctors with critical diagnostic information quickly and reliably. During a recent
installation, as Heartlab technicians were in the process of transitioning a cardiology
lab off film and onto the cardiac network, Petrocelli says a cardiologist was able to
locate a lesion on a heart valve that he hadn't seen. In the end, that patient made a
complete recovery. |
|
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| Article Date: |
June, 2000 |
| Magazine Volume: |
4 |
| Issue: |
6 |
| Author(s): |
| *Zachary
Shess |
-
InfoStor |
|
|
|
