Found this interesting little tidbit posted by hemena on the MTIC yahoo message boards:
Monday February 14 10:33 PM EST
IBM storage server hits speed bump
By Sonia R. Lelii, PC Week
IBM's prized storage server, known as Shark, is being weighed down by glitches that can
degrade performance.
Specifically, Shark, officially called the Enterprise Storage Server, suffers from a subpar PCI
interface that is causing serious bottle necks and other glitches,
according to customers and analysts.
The problems are not only a blow to customers but also a black eye to Big Blue itself, which
touted Shark as its "EMC killer" disk
array when it debuted last July. For all intents and purposes, Shark was to be the IBM machine
to help the company recapture lost
market share from chief rival EMC Corp.
IBM has sold about 1,600 Shark machines to date.
Shark is designed to scale up to 11.2 terabytes, compared with EMC's Symmetrix, which
scales to 9.2 terabytes.
But some early Shark customers say they're not close to approaching that type of storage.
Family Dollar Stores Inc., of Charlotte, N.C., has traded in four Symmetrix devices for one
Shark. Allan Davis, director of technical
services at the company, is pleased with the machine but acknowledged that IBM officials
warned him that Shark experiences
performance penalties when it hits a certain storage amount.
"If I go to 1 or 1.2 terabytes of information, I need to go to a second Shark," he said. Davis is
currently storing 350GB of data on the
Shark system.
IBM contends that performance is tied to the type of application that works on the hardware.
At the heart of the machine's problems, according to Meta Group Inc., is the PCI interface.
Shark's predecessor, the Versatile Storage Server, also known as
Tarpon, also experienced PCI problems. IBM officials in Armonk, N.Y., said the company has
resolved those issues.
"It's a new PCI interface that provides enhanced operations over Tarpon," said Mike Harrison,
director for storage systems marketing at IBM.
The Tarpon PCI bus ran at 132MB per second. Theoretically, Shark's four PCI buses have a
cumulative internal bandwidth of up to 800MB per second.
But the use of multiple PCI interfaces can degrade performance. "We still believe [Shark's]
overhead poses a potentially serious performance issue," said analysts
at Meta Group, of Stamford, Conn., in a paper published last fall.
Just why Shark is outfitted with such a design could boil down to the fact that it was rushed to
market. IBM was rapidly losing market share to EMC, and some
analysts criticized IBM for releasing Shark prematurely as it lacked such essential storage
features as Fibre Channel connectivity and virtual architecture.
Now, five months after its September release, questions surrounding the PCI interface and
microcode are once again raising skepticism over its readiness for prime
time.
This may eventually prove moot, however, as Meta Group's report suggests that the machine's
performance should be improved by the fourth quarter, when IBM
unveils an enhanced PCI-E bus.
IT managers at First Union National Bank questioned IBM officials about Shark's PCI
interface because of the company's earlier dismal experience with Tarpon.
"[Tarpon] failed while we were just starting to kick its tires," said George Mattingly, senior
vice president and director of capac ity planning at First Union, also in
Charlotte. "We found it had at least one single point of failure," the PCI interface.
Mattingly said IBM's engineers admitted to the bus problem in Tarpon and assured him the
problem was fixed for Shark.
But, ultimately, the banking company went with EMC's Symmetrix because, according to
Mattingly, EMC could deliver its product faster. Today, First Union has
140 tera bytes of storage.
In addition to the bus issue, a couple of major IBM customers have experienced some base
function microcode problems with the storage system. IBM officials
acknowledged that some microcode problems have emerged but said that is normal for a new
system.
But that's no excuse, according to one IT manager who asked not to be named. "IBM is not
new at this. It's been playing in this market a long time," he said.
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