SSD news - June 8 -
14, 2011
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world's first PCIe PCM SSD
Editor:-
June 14, 2011 - NVSL ( the
Non-Volatile Systems Lab at UCSD) recently
demonstrated
a prototype PCIe PCM (phase-change memory) SSD - with R/W speeds upto 1.1GB/s
and 327MB/s respectively and 8GB usable capacity.
A spokesperson for
the Moneta SSD design team - Professor
Steven Swanson said "...Moneta gives us a window into the future of
what computer storage systems are going to look like, and gives us the
opportunity now to rethink how we design computer systems in response."
Swanson says he hopes to build the 2nd generation of the Moneta
storage device in the next 6 to 9 months and says the technology could be ready
for market in just a few years as the underlying phase-change memory technology
improves.
Editor's comments:- in a white paper
Protoype
PCM Storage Array (pdf) the team outlines the design and architecture of
their PCM SSD prototype and also compares aspects of performance with entry
level PCIe flash SSDs from
Fusion-io. In a
recent article
I warned that you should not pay too much heed to comparative PCIe SSD
benchmarks - because from different arbitrary selected angles they can "prove"
different arbitrary performance rankings. I wouldn't be surprised if some
investors take fright that a PCM SSD scored higher than a Fusion-io SSD in some
of the published graphs. But for those who understand SSD architecture it
doesn't reveal anything new.
In my view this prototype clearly
demonstrates the strengths and weaknesses of PCM as an SSD technology.
PCM SSD strengths vs flash
The granularity of writes
in PCM is smaller and faster - which means that small R/W operations have higher
IOPS. If you have apps where that is important you can simply buy
SSDs with various
ratios of integrated RAM cache. That would give you small block IOPS
better than PCM - end of story. PCM has higher
endurance
than SLC - which means that the
SSD controller
overhead applied to endurance can be lighter than in most flash systems. Hence
potentially faster latency through to the media.
PCM SSD
weaknesses vs flash
The prototype PCIe SSD card provides capacity
which is similar to RAM SSD
density - but with a large block R/W throughput which is much lower than
flash arrays. This
implementation used 16MB PCM chips.
Flash allows higher capacity writes
to a single chip - and this gives better peak performance results than PCM when
exploited in parallel architecture arrays. You can't get those flash peak
performance numbers from a PCM array in the same board footrpint - because many
PCM chips have to be written to concurrently to achieve the same capacity R/W
as a single flash chip. That means with today's technologies - flash SSDs
have a higher proportion of ready to write memory chips in the same chip count
population as PCM SSDs.
For more about alternative SSD technologies -
see SSD's past phantoms.
SANBlaze ships PCIe to 1.8" SSD RAID adapter
June
13, 2011 - SANBlaze
Technology is shipping a new
rear
transition module which connects upto 8x
1.8" SSDs to
PCIe with
RAID options.
BiTMICRO - update from an SSD pioneer
Editor:- June
13, 2011 - BiTMICRO
was one of the original flash
SSD pioneers
in the 1990s - and they did a lot to advance the notion of using flash
SSDs to accelerate servers.
In a
2004 case
study they showed how a single
3.5" flash SSD
speeded up a 25,000 user server by 15x compared to the previous HDD
storage system.
But I hadn't heard much from them in recent
years. So I welcomed the chance of getting an update from the company.
I asked BiTMICRO's Marketing Manager - Cecilia Martorillas to tell me
where they are on the
MLC / SLC flash
question - as most of their business now seems to be in the industrial /
military market. You can see what Cecilia said and
learn more about BiTMICRO
by clicking here.
Compliance issues in Cloud Storage
Editor:- June
10, 2011 - A recent article in
InformationWeek.com
discusses the use of cloud
storage for
archiving.
Among
other things - the author George
Crump warns that - "The deletion of data from the cloud may be the
most overlooked consideration." ..read
the article
Editor's comments:- - judicious deletion
is also a strategic issue for long established web sites too. GerryMcGovern discussed that in
his classic article -
the
Business case for deleting content. |
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