By Heidi Biggar
Although integral components of storage area networks (SANs), until recently tape drives have relied on bridges or routers to perform necessary SCSI to Fibre Channel conversion. However, both StorageTek and Exabyte have announced native Fibre Channel interfaces for their 9840 and Mammoth-2 technologies, respectively, which eliminate the need for these devices.
"It's a much easier, straightforward implementation if you don't have to put a bridge or router in your SAN configuration," says Gary Francis, StorageTek's vice president of corporate strategy. The 9840FC can be directly attached to arbitrated loop or switched fabric Fibre Channel SANs for centralized storage management, without the distance restrictions of SCSI and with potential performance and cost benefits, Francis claims.
"In some cases, you may actually improve performance because you don't have to go through protocol conversion," explains Francis. "Protocol conversion equals overhead, which can impact performance." STK claims that five 9840FC drives can do the job of 10 to 20 midrange SCSI tape drives.
However, other tape library vendors, such as ATL Products and ADIC, believe the benefits of native Fibre Channel tape drives aren't so clear-cut. "The proof is in the pudding," says Shaun Walsh, director of product marketing at ATL. "Until we see Fibre Channel drives, it's impossible to speculate how low their costs will be [relative to bridges/routers] and how high their reliability will be [relative to SCSI drives]." To be economically viable, native Fibre Channel drives need to cost less than a SCSI drive/bridge combination and they need to be as reliable as SCSI drives, according to Walsh.
As for performance, most vendors don't expect immediate gains. "Native Fibre Channel won't give an immediate throughput advantage, especially if data transfer is still going through servers," explains Steve Whitner, director of marketing at ADIC. "A lot depends on the size of the server and the type of applications being run."
On the upside, native Fibre Channel tape drives permit longer cabling distances, simplified SAN attachment, and improved scalability.
While other vendors are expected to follow suit with native Fibre Channel tape drives as early as this summer, analysts do not expect widespread adoption of native Fibre Channel tape products until the 2001-2002 time frame.
"At this point, native Fibre Channel drives are checklist items," says Bob Amatruda, a senior analyst at International Data Corp., a market research firm in Framingham, MA. "I don't expect them-or Fibre Channel-enabled libraries-to show up in any volume for 18 to 24 months."
StorageTek began production shipments of native Fibre Channel tape drives in December; Exabyte announced general availabiltiy last month. To date, StorageTek says it has shipped more than 600 9840FC drives.
With a native 20GB capacity, 10MBps transfer rate, and an 11-second average search time, StorageTek's 9840FC is geared toward high-performance e-business and digital/video applications. Based on a single-chip QLogic ISP2100A processor, the drive can be integrated into StorageTek's L180 library-announced with the tape drive-for a "full-Fibre" system. The Fibre Channel drive lists for $34,000, compared to $27,000 for STK's SCSI alternatives.
Targeting midrange markets, Exabyte formally launched Fibre Channel Mammoth-2 at this month's NAB show. Like STK's 9840FC, the Fibre Channel version of the Mammoth-2 drive is based on a QLogic processor. The drive is available in internal and external models, and has a maximum 60GB native capacity and a 12MBps native transfer rate.
The internal drive lists for $5,395, the external drive with two GBICs lists for $5,695-$500 more than comparable Mammoth-2 SCSI LVD models.
And Sony, once considered the forerunner in this area with its Comdex 1998 announcement, says it now expects to ship native Fibre Channel DTF-2 tape drives late this summer. Instead of its intial plan of a single drive with field-exchangeable interface modules that slip into an integrated PCI bus, Sony will offer two distinct drives-one SCSI (the GY-8240UWD), the other Fibre Channel (the GY-8240FC). The Fibre Channel drive will integrate a QLogic processor.
Meanwhile, other tape library manufacturers continue to take a wait-and-see approach to native Fibre Channel drives, focusing primarily on bridge or bridge-like products for SAN integration (see this month's New Products for the latest SCSI-to-Fibre Channel bridges).
Vice president corporate strategy, StorageTek