Emulex, Seagate Technology and Xyratex Technology have
collaborated to produce the first full-function 4Gbit/s demo, with
Xyratex's storage enclosure technology, Seagate's 4Gbit/s
enterprise HDDs and Emulex' InSpeed SOC 422 Fibre Channel embedded
storage switch.
The working 4Gbit/s Fibre Channel network goes on show at Cebit
this week. The demonstration will show that end-to-end 4Gbit/s
networks require HBAs, switches, drive arrays and drives all to be
4Gbit/s-capable.
Most Fibre Channel Sans operate at 2Gbit/s. A forthcoming
10Gbit/s Fibre Channel network will offer five times faster links
but will not be backwards-compatible with today's 2Gbit/s switches,
HBAs and drive array controllers. As such, an interim 4Gbit/s
standard has been developed to add a little more speed and work
with existing 2Gbit/s gear.
QLogic has also been at the forefront of efforts to have 4Gbit/s
fibre channel adopted, but the company is hedging its bets and
promoting 10gig as well.
With companies such as Brocade Communications Systems suggesting
multi-level Sans are a development for the future, then San
backbone links will need to aggregate multiple-edge links. A
4Gbit/s backbone would only be able to aggregate two existing
2Gbit/s links. A 10Gbit/s link would be more effective. There is
also little evidence as yet that customers are suffering from the
San slowdown that would encourage the use of faster Fibre
Channel.
However, 4Gbit/s Fibre Channel hardware products are
pin-compatible with 2Gbit/s products and the chips involved will be
little different in cost, meaning it will be easy to upgrade. The
alternate Ethernet-based iSCSI San technology will move directly
from 1Gbit/s Ethernet to 10Gbit/s and that could force the
issue.
Or, 4Gbit/s Fibre Channel may offer too little. By the time San
speed needs have become more apparent, 10Gbit/s products will be
available and ready to take up the slack.
Chris Mellor writes for Techworld.com