New SAS products spark debate-新型SAS产品引发争论

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  Serial attached SCSI
seems like it's been a long time coming, and given all the time to hurry up and wait, there are already
new schools of thought emerging about where the new interface will fit
in the data center. Some industry experts feel SAS will replace
SATA
; others that it will threaten
Fibre Channel
;
but the recently announced SAS products, other analysts say, show that
SAS ultimately might not end up completely replacing either.
  Infortrend announced the EonStor® (ES) S12F-R1420 4
Gigabit
(4Gb) Fibre Channel to SAS
RAID

array
on Sept. 26. Infortrend's president, Tony Chu, said he expects the box
to begin shipping by the fourth quarter. Promise Technology Inc. also
just launched the VTrak J300s SAS to SATA
JBOD
subsystem, expected late in the fourth quarter. Both companies said
they expected the SAS market to really take off early next year.
Chu said he was in line with those who think SAS may drive Fibre
Channel out of the data center, given its comparable reliability and
much lower cost, but would leave SATA plenty of market share.
" Unless SAS prices go way, way down, SATA will still be used in many secondary storage places,"  he said.
Meanwhile, he said he felt SAS offered better connections between
devices than Fibre Channel. " Fibre Channel connects so many devices on
one loop, and every one shares the same bus," he said. " SAS offers
much simpler point-to-point connections."
Meanwhile, however, some experts have speculated that, instead, it will
be SATA that will be displaced by SAS, since SAS, typically a higher
quality drive, can slide so easily into SATA-based arrays.
" They coexist very well together," said Thomas Bayens, director of
corporate marketing for Promise Technologies. " They can both plug into
the same backplane, where SAS and Fibre Channel's interoperability is
kind of a question mark."
Some industry analysts, meanwhile, say neither FC or SATA is
necessarily totally threatened by SAS, and that it might find its own
place in the data center.
According to Arun Taneja, SAS could become a go-between for FC and SATA
drives, which currently don't talk to one another without separate
bridging technology. " If FC is a strong connectivity mechanism and
SAS/SATA are compatible at the slot level, why not create FC-SAS, where
by the customer could enjoy creating two tiers of storage in the same
box?" he said.
" Bridges add cost and complexity to products. A protocol that makes FC
understand SATA without a bridge… has not been ratified by any
standards body yet... So for now SAS-SATA interaction is smoother,"
Taneja said.
 According to Greg Schulz, analyst with the Evaluator Group, SAS will
elbow its way into the data center, driving virtually every other
technology out of at least some markets. " Over time, there probably
will be some cannibalization of the FC disk space by SAS as it makes
its way into enterprise arrays," Schulz said. " On the low end, it's a
different game, there
SCSI
will be replaced by SAS and I would expect that some
IDE
,
ATA
and SATA implementations might be replaced by SAS as well as costs come down… SAS could also be pitted against
iSCSI
and
NAS
in some of these environments."


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