This page is mostly
about hybrid storage drives - in which a
hard drive is packaged
in the same proprietary (factory integrated) drive module as an
SSD.
The success
or failure of how this type of product works depends a lot on the design and
cost of the
controller which
shares the data between the 2 types of media (or 3 types - if you include the
RAM cache in a
flash SSD.)
I've created a special interest page -
SSD ASAPs -
which discusses the auto tuning of storage pools for enterprise apps - and that
also has some discussion of the ASAP concept when applied to
notebook SSDs. |
| . |
will OCZ's new hybrid SSD
be a market game changer?
Editor:- September 1, 2011 - OCZ yesterday
launched a
hybrid PCIe SSD - the
RevoDrive Hybrid - which integrates 100GB SSD capacity along with an onboard
terabyte HDD and
SSD ASAP / auto hot spot
cache tuning controller capable of 910MB/s peak throughput and upto 120,000
random write IOPS (4K) - all for an MSRP under $500.
"The
RevoDrive Hybrid leverages the best attributes of both solid state drives and
traditional hard drive technology to deliver dynamic data-tiering on a single
easy to deploy PCIe storage drive," said Ryan
Petersen, CEO of OCZ.
Editor's comments:- although
many oems have tried to make a success of
all in one SSD-HDD
hybrid drives - the hybrids which have come to market in the past 6 years
have mostly been failures - as I predicted back in 2005 they would be. That's
because there's an infinite number of permutations which designers can choose
to blend the mix of interface, SSD and HDD capacity and budget - whereas there
is only a small and finite market in which any such combination of features will
work and be competitive. Many past hybrids have also failed to ignite user
buying chain reactions - because they were too slow - having been designed with
interfaces which were too slow, controllers which didn't work, and not enough
SSD capacity relative to the hard drive storage.
OCZ's new product
therefore is coming into a market which has been littered with the bodies of
past failures from other larger storage oems. What's different - and what
could make a difference in this case - is that the ratio of SSD capacity to
typical desktop RAM is a usable number (it's been much too low in all previous
hybrids from hard disk makers) and the ratio of SSD to HDD looks right too. And
the interface - PCIe means that the controller latencies won't get in the way
between the host and the SSD - which has been a weakness in SATA based hybrids.
Therefore it looks like a balanced design.
Is there a big enough
market for this exact combination of features? OCZ with its track record of
high performance consumer SSD sales is better placed to judge this than most SSD
companies (and most analysts).
If any hybrid SSD is going to provide the kind of user experience which leads
users to spread the word and become part of the sales force - this one might
well just be it.
Jim Handy says hybrid drives will replace HDDs in mainstream PCs
Editor:-
October 25, 2010 - Objective Analysis
has published a new market report
Are
Hybrid Drives Finally Coming of Age? - ($5,000 54 pages).
It
explains hybrid drive technical principals, the technology's potential market,
competing technologies, and how the NAND, PC,
SSD, and
HDD markets will all be
impacted by this new twist on an old technology.
The report tells
why the technology failed in the past, and forecasts its anticipated growth.
Objective Analysis says this technology was well conceived but poorly
implemented in its first generation. Now that working versions have been
implemented the hybrid drive promises to sweep the PC hard drive market.
"We expect the
hybrid drive
market to nearly double every year for the 5 years following its initial
adoption, reaching 600 million units by 2016," said the report's author
Jim Handy. "This
blazing growth will result from hybrid drives replacing standard HDDs in
mainstream PCs."
Editor's comments:- this is the scenario which
Seagate is hoping will
come true - according to their recent statements.
In contrast
StorageSearch.com's view is that instead of hybrids - users will do better using
vanilla SSDs in light weight notebooks and in higher capacity notebooks
using a combination of vanilla SSD (on the motherboard) working with vanilla
HDDs tuned by SSD ASAP
techniques (controller or software).
The market will decide which
approach they prefer. For more differences of opinion about how solid state
storage should fit in with computer architecture see
the SSD Heresies.
NVELO launches notebook SSD ASAP
Editor:- August 17,
2010 - NVELO
launched
Dataplex - a software product
aimed at PC oems - which provides
SSD ASAP
functionality inside a
notebook.
Since Dataplex works with off-the-shelf storage devices, PC OEMs and
consumers have complete freedom to choose any SSD and any HDD, from any vendor.
"Consumers love the idea of SSD performance, but there is still a
huge (price) gap
between HDDs at $0.20/GB and SSDs at $2.00/GB; as an HDD replacement, the
economics simply don't work for all but a very small percentage of the market,"
said David Lin, VP of product management at NVELO. "With Dataplex, we are
making SSD performance economically feasible for a much larger market by using
the strengths of SSD and HDD technology together. And we're not talking about
simply installing the OS and whatever applications can fit onto a small SSD.
Dataplex learns user behavior, and intelligently caches all important data and
applications in an SSD device while maintaining the full capacity of the HDD for
storage."
Dataplex will begin shipping from select Tier 1 PC OEMs
in 2011. NVELO is currently in discussions with leading
HDD and
SSD vendors to enable
aftermarket sales and bundling options for Dataplex, and has begun development
of an enterprise version of Dataplex for server systems.
Editor's
comments:- if successful - NVELO's product will render obsolete most
hybrid drives
aimed at the notebook market. In the server ASAP market - it's a direct
competitor to the unloved
MaxIQ
SSD Cache Performance Kit created by
Microsoft, taken to
market by
Adaptec - and now owned
by PMC-Sierra.
Seagate launches hybrid for notebooks
Editor:- May
23, 2010 -
Seagate today
launched the
Momentus
XT a 2.5" hybrid
drive - for the
notebook PC
market - which internally has a 500GB
HDD cached by a 4GB
SSD ASAP controller.
Seagate
says the new drive is OS agnostic and delivers
SSD-like
performance at the lower
price of a hard
drive.
This isn't a new concept - as you can see on this
archived
product page for the Platinum HDD from March 2008. Except that pioneering
old product from DTS was a
3.5" form factor and used a
RAM SSD. (Since then
DTS has moved on to market a
fat flash SSD
- called the Platinum M-Cell
SSD.)
In 2006 the reputation of hybrid hard drives in notebooks
(as a poor man's SSD placeholder) was ruined by the poor performance of
Microsoft's
ReadyDrive support in VISTA. So experienced users may be cautious about
Seagate's new product. Anyone who needs serious PC application performance
won't be wasting their time with a hard drive.
When Seagate introduced
7,200
RPM HDDs in 1992 computer users were impressed by its performance. But
Seagate's press release headline today - "World's Fastest Hard Drive for
Laptop Computers" - is a bit of a joke. Because hard drives aren't fast.
2.5" hybrid flash SSD/HDDs are a waste of space - says
StorageSearch.com's editor
Editor:- May 17, 2010 - a recent
article in
TheRegister.co.uk
discusses prospects for the
hybrid SSD/HDD
market and includes the above quote from yours truly.
The article,
written by experienced storage commentator
Chris Mellor,
came out of a discussion that
Toshiba might be thinking
of new hybrid SSD products.
As readers know I always have an opinion
about everything - but as I thought the Toshiba idea was not a very good one -
I didn't want to waste my time writing about it. Chris asked why I thought
that - and as a result he has written a much better article than I would have
done myself anyway. ...read the
article
...Later:- after seeing the above article -
a long time SSD reader reader asked me to say more about about my dismissal of
single hybrid drives for consumer markets.
While agreeing that past
solutions in this market had failed - he asked if the
SSD ASAP concept
couldn't be scaled down to a single flash SSD cached hard drive.
Here's
what I said.
As you aware many companies have tried to include various
caching schemes to leverage the benefits of a small amount of flash SSD capacity
compared to a larger amount of HDD capacity. There are also companies in
stealth mode looking at this problem. I think when it comes to the consumer
case - economics and the philosophy of computer architecture clash in an
irreconcilable way.
If we look closely at the detail we meet all kinds of problems -
which individually seem solvable - but taken together aren't.
1 - SSD caching applications have to be designed with a particular
data usage model in mind. An algorithm that works for 1 type of app may be
useless for another - and in the worst case give even worse performance than no
caching at all.
2 - The best results for SSD speedup are when the CPU is limited by
the IOPS it is seeing from the HDD system. Enterprise motherboards are mostly
designed so that peripherals can get access to a fast processor type of bus
(originally designed for comms etc) and it's possible to access more latent CPU
power than is used by HDD systems. But the budget conscious nature of consumer
notebooks
means that there usually isn't much CPU headroom available. If there was - it
would mean that the design was using too much battery power - or the oem was
paying for faster chips than
it needs for most application.
But if we take a step up from all these issues - there is another
obstacle in the current market which works against the idea of an SSD ASAP for
consumer platforms.
The success of flash speedups in an SSD is due
to the SSD controller.
If you have a small capacity flash SSD - most of the cost is in the controller
and not in the flash.
Speeding up the flash SSD controller to make it better able to manage
a hybrid storage pool is possible - but at some point the cost and power of this
SSD CPU will be higher than that of the notebook CPU to which it is connected.
That's why - it's economically unlikely to happen - regardless of the caching
algorithm.
In the long term notebooks should be designed with the chipsets
optimized for SSD (with CPU headroom - like portable servers in architecture).
I don't think any flash SSD / HDD hybrid for consumer apps will be good value
for money - unless it is designed for 1 particular application. In that case the
market segment will be so small it won't be viable.
For apps like playing video - your don't need SSDs - because the
sequential pattern of data usage matches HDDS well. (It's different for video
servers - because when you have hundreds or thousands of users - you can't
dedicate a fixed fraction of a physical disk stream to each. That's where SSDs
are useful.)
XLC invites HDD partners for "enterprise" x4 hybrids
Editor:- April 1, 2010 -
XLC Disk
announced details of a paper it will discuss later this month at the NV
Memories Worskhop (UC San Diego) called - Paramagnetic Effects on
Trapped Charge Diffusion with Applications for x4 Data Integrity.
The
company says its findings could have applications in the enterprise storage
market by solving the data integrity problems in x4 MLC SSDs within a new class
of hybrid storage drives. ...read more
Avere Launches Hybrid NAS SSD Rackmounts
Editor:-
October 5, 2009 - Avere
Systems unveiled its
FXT Series of
clusterable 2U rackmount
hybrid
NAS appliances.
Each
module contains upto 8x 3.5"
SAS
hard drives, 64GB
DRAM and 1GB of
nv RAM. The embedded
Avere OS
provides storage acceleration by dynamically tiering between the internal
rotating and solid state storage. List pricing starts at $52,500.
"The FXT Series is a milestone in the evolution of storage
products with its dynamic use of storage media to maximize speed while
minimizing cost," said Ron Bianchini, co-founder and CEO of Avere Systems. "The
end-result is a product line that can deliver tremendous business value to
customers by providing high performance and high efficiency to the storage
network simultaneously."
Editor's comments:- Avere is the
3rd company in recent weeks to announce an automatic solution for the age old
problem of accelerating
legacy hard disk array applications with solid state storage. There are
some interesting differences in approach and target markets.
Avere's
product is aimed at NAS
systems. It's a complete end user solution which includes the hard disks
which are to be accelerated. Avere says the new product can be configured with
upto 1.6TB of DRAM per cluster.
Dataram's product is
aimed at SAN systems.
It's an end user upgrade solution which fits between the customer's
FC switch and
pre-existing SAN rotating storage arrays. In some cases where users have already
over provisioned hard disks - the
XcelaSAN
may also, as a side effect, increase the usable storage capacity as well as
speed up the apps.
Adaptec's
product is aimed at DAS
systems. The
MaxIQ
SSD Cache Performance Kit an integrator / oem solution which simplifies
the task of building a hybrid storage pool.
Key questions for customers
are going to be:- Does it work? How does the price / performance compare to
vanilla SSDs and human tuning? And how
reliable are the
new products going to be? Understanding the
failure modes in
large SSD arrays is not something that traditional storage designers know
very much about.
Adaptec Enters the SSD Market
Editor:- September 9,
2009 - Adaptec
announced a new platform for integrators building
hybrid storage
pools using SSDs.
Its
MaxIQ
SSD Cache Performance Kit (which operates with upto 4x customized 32GB
Intel SSDs) includes
software that identifies frequently (hot) read data blocks and optimizes
subsequent "reads" by moving "hot" data directly into the
SSD cache for lower latencies and higher system performance.
Adaptec
president and CEO Sundi Sundaresh said that the new product "Underscores
the potential that we see for significant future management and conditioning of
data through the I/O path, which is central to our new ... strategy."
DTS Hybrid SSD Wins Best of Show
Editor:- June 12,
2009 - DTS today
confirmed it has won a
best
of show award at Interop
Tokyo 2009 for its Platinum SSD.
Editor's comments:-
DTS's original Platinum drive was a
3.5"
hybrid - which
included a RAM SSD accelerated
hard drive. The
internal SSD controller
virtualized the interface to make it appear as an OS agnostic
SATA drive.
More
recent versions of this drive embed a
flash SSD (instead
of HDD). The best way to think about this product is as a scaled down single
disk version of an SSD
accelerated RAID. It can significantly increase random IOPS for some types
of application - at a cost which nothing else comes close to (using SLC
flash technology). It's scalable too. Some DTS customers use these drives in
rackmount arrays.
This is the kind of product which requires extensive
benchmarking in the production environment in which it's going to be used. If
it's a good fit - then great. But actual speedup and competitiveness depends on
a variety of factors which are too difficult for most users to model. DTS says
it will ship a 2.5" SSD which delivers about 40,000 IOPS later this
month.
Sun Responds to User Needs for More SSD Capacity
Editor:-
May 27, 2009 - Sun
Microsystems announced today it has
improved
its hybrid rackmount storage systems to support an additional 600GB of
flash SSD cache (compared to the current 64GB internal limit) for enhanced
application performance.
The Sun Storage
7310
is available today and starts at a price of $40,165.
Editor's
comments:- terabyte SSDs become commercially available in
2002 - so
Sun's initial product offering last November - which supported a mere 36GB per
4U rack - was a sure sign that the company either didn't know what it was doing
- or was being overly cautious.
There are plenty of
rackmount SSD
vendors in the market - and soon there will be hundreds more. There's wide
diversity in product architectures (open versus proprietary) and applications
experience in this part of the SSD market (ranging from months in the case of
Sun - to more than a decade for companies like
Solid Data Systems and
Texas Memory Systems).
If
you are thinking of buying an SSD from Sun - timing the purchase is a something
to think about. In recent years Sun used to steeply discount towards the end of
its quarter. I'm not sure how being part of
Oracle will
affect that. See also:-
Hybrid Storage
Drives
DDRdrive Launches Low Cost PCIe RAM SSD
Editor:- May
4, 2009 - DDRdrive
emerged from stealth mode and launched the
DDRdrive X1 - a
PCIe compatible
RAM SSD with onboard
flash backup. |
| Load / restore time is 60S. I/O
performance is over 200K IOPS (for 512B blocks). For 4kB blocks IOPS is:- 50k
(reads) and 35K (writes). R/W throughput is 215MB/s and 155MB/s respectively.
Capacity is 4GB. OS compatibility:- Microsoft Windows (various). Price is
$1,495. |
..... |
 |
| ............................................................................... |
| Using Microsoft Windows
built-in RAID support,
DDRdrive X1's can be spanned (capacity), striped (performance), mirrored
(redundancy), and RAID-5 configured. | |
Editor's comments:- the
DDRdrive X1 looks competitively priced for accelerating database applications in
which the hot files can be squeezed into a capacity range from about 4GB to
12GB. Above that - you get into the region of entry level
rackmount SSDs
and high performance PCIe
flash SSD cards
from companies like Fusion-io
and Texas Memory Systems.
There's definitely a gap in the market for this scale of product (low
entry price, low capacity - high IOPS). For the past year or so DDRdrive
shipped an earlier generation of its SSD accelerators exclusively to a large
enterprise for secret internal projects.
Samsung Announces 40nm Geometry for Flex-OneNAND
Seoul,
Korea - March 10, 2009 - Samsung
Electronics - today announced that it has begun using 40nm process
technology to produce an 8Gb
Flex-OneNAND
fusion memory chip.
Flex-OneNAND incorporates
SLC and MLC NAND on
a single piece of silicon, allowing application designers to choose the portion
of SLC and MLC NAND storage to be used in any particular design through a simple
adjustment to the accompanying software. This maximizes the performance and
efficiency of the embedded flash chip. storage chips
DTS Launches Fastest 3.5" SSD
San Jose, CA - February 17, 2009 - DTS,
Inc today announced availability of the fastest 3.5" SATA SSD -
the Platinum HDD 2009 model.
Internally it has a 1GB
RAM SSD which operates
as a non volatile RAM cache for an internal
flash SSD (320GB
to 512GB). Aimed at server acceleration applications performance is 25,000 R/W
IOPS, read speed is 250MB/s, and write speed is upto 240MB/s. DTS says the huge
nv cache also attenuates writes (the opposite of write amplification) - thereby
reducing flash wear by x10 to x400 compared to conventional flash SSDs. ...DTS profile
Editor's
comments:- in my article
Predicting Future Flash
SSD Performance I noted how having a non volatile RAM cache is a key
architectural factor in flash SSD tune ups.
In the
rackmount SSD
segment the RamSan-500
from Texas Memory Systems
(launched September 2007) and in the
2.5" form factor
the ESSD from
Memoright are other
examples of this type of implementation.
DTS's original Platinum drive
(launched a year ago) was a hard
disk / RAM SSD hybrid. The new 2009 model benefits from the faster IOPS
performance which stems from embedding a flash SSD instead of HDD. It also
builds on the experience of refining the internal cache which
accelerates many types of server app - without any modification to the
application software. You just install it like a hard drive. DTS says it's
particularly good for VMware and similar multiple client environments. Their
website includes comparative benchmarks.
Sun Launches Hybrid Rackmount Storage
SANTA
CLARA, Calif. - November 10, 2008 - Sun Microsystems, Inc. today
announced the availability of its new 7000 family of rackmount storage systems
- which includes hybrid HDD / flash SSD arrays.
Sun says its
Solaris ZFS can use SSDs intelligently as a cache for both application and file
system metadata, placing latency-critical data structures appropriately on flash
media and using algorithms to optimize data placement. In addition, Solaris ZFS
provides acceleration of both read and write operations, and lets administrators
configure the system to match workload demands. ...Sun Microsystems profile,
rackmount SSDs
Verari Announces Intel-SSD-Inside Hybrid Storage Blade
DALLAS, TX. - October
15, 2008 - Verari Systems today announced HyDrive, a hybrid
enterprise storage blade.
The new Verari HyDrive disk blade
integrates Intel's X25-E
2.5" SSD as well
as high capacity 3.5" SATA hard drives into Verari's
BladeRack 2 X-Series
platforms. ...Verari
Systems profile, rackmount
SSDs
Cypress Integrates Non Volatile Static RAM in Controller
Editor:- September 22, 2008 - Cypress Semiconductor
introduced the industry's first device to integrate a non-volatile static random
access memory and a programmable system on chip.
This may be useful
in future hybrid designs of
very fast flash SSDs
which could use nvSRAM in the controller and thereby deliver better latency for
small random reads / writes.
Silicon Motion Enables New Type of Hybrid Flash SSD
TAIPEI, Taiwan - June
23, 2008 - Silicon Motion Technology Corp today announced the launch
of 3 new SSD controllers.
"We are already a market leader in the SSD controller market,
especially in the low cost notebook PC segment. We shipped almost 1 million
units of SSD controllers in 1Q'08, which is more than any other company in
the world" said Wallace Kou, CEO of Silicon Motion.
The new
controllers can support hybrid SSDs that use a combination of SLC and
MLC NAND flash to minimize device cost and maximize endurance. SM2240, for
example, can manage a 64GB SSD using 8GB of SLC and 56GB of MLC flash. Through
sophisticated and innovative algorithms, the controller is able to analyze the
incoming files from the host and intelligently move frequently accessed data to
SLC NAND and non-frequently accessed data to MLC NAND. With this hybrid
architecture, the SSD system cost is significantly reduced to a level comparable
to a pure MLC-based SSD, while endurance is significantly enhanced and
comparable to a pure SLC-based SSD. ...Silicon Motion
profile
Editor's comments:- this new class of hybrid SSDs is
one way to fix the endurance problem faced in cost conscious server apps that
are only viable with MLC type budgets. Another solution is
EasyCo's MFT - which
inherently reduces writes while increasing write IOPS through a host resident
driver. But some of the other risks revealed in my article
Are MLC SSDs Safe
in Enterprise Apps? haven't gone away.
Hybrid Hard Drives Market Report
Los
Gatos, CA - December 19, 2007 - The Hybrid Hard Drive will not make a big
splash in 2008, according to a new 36-page report by Objective Analysis.
PC users who are waiting for this technology to speed their boot
times are going to have to wait a little longer.
"Once all the kinks are ironed out, hybrid drives and their
counterparts should sweep the market," said Jim Handy, the report's author.
"Unfortunately, the hardware is ready but the software support is weak.
Hybrid drives will have to wait for better support to justify their small
additional cost."
Hybrid Hard Drives: How, Why, And When? - is an in-depth review of
the hybrid hard drive market, exploring the technology, implementation costs,
and expected benefits, as it explains why those benefits are not within reach
today. The report takes a special look at alternative technologies like SSDs,
Intel's Turbo Memory, the
SanDisk Vaulter Disk,
larger DRAM main memories
and DRAM HDD caches, and even small SSDs from
Samsung. The report
reviews members of the Hybrid Storage
Alliance members and details their product offerings.
Readers will learn how hybrid drives work and why they are receiving
so much attention today. They will also understand why hybrid drives will
threaten the SSD market, and why neither technology is likely to see much
acceptance until the second half of 2008 or later.
...Objective
Analysis profile
IDC Report Casts Doubt on Hybrid Hard Disk Market
FRAMINGHAM, Mass
- January 23, 2007 - IDC has published a new report called - "Outlook
for Adoption of Hybrid-HDD or NAND in PCs" It says that so far,
neither the hybrid hard disk drives nor embedded NAND flash technology
convincingly realizes the potential of caching in Vista PC and therefore,
neither can be considered the clear winner. Also the emergence of NAND
flash-based solid state disks
could disrupt the brewing NAND caching technology battle.
...IDC profile
Hybrid Storage Alliance Aims to Speed Up Notebooks
Storage Visions 2007 Conference - January
4, 2007 - Hitachi, Samsung, Seagate and Toshiba
have formed the Hybrid Storage Alliance.
The goals of the
industry group are to illustrate how flash memory/hard drive hybrid
technology can extend the capabilities of today's notebook computers and to
accelerate market adoption of the technology.
IDC predicts hybrid hard
disk drives will constitute 35% of all hard disk drives shipped with portable
PCs by 2010.
Hybrid hard drive technology is the industry's answer to growing
demand for notebook PCs that deliver the speed and durability of desktop PCs.
Hybrid technology, which can be deployed in other mobile devices and computing
systems, combines the unmatched capacity and cost-effectiveness of hard drives
with the responsiveness, power-efficiency and durability of flash memory.
...Hybrid Storage Alliance,
Storage Industry Trade
Associations |
| . |
|
| |
 |
| And this bit goes with that. | |
| . |
|
|
| . |
| "...2.5 inch hybrids
are a waste of space.." |
| ...Editor
interviewed in -
TheRegister
- in May 2010. | | |
| . |
 |
|
|
July 1, 2008 - by
Zsolt Kerekes
editor |
My immediate reaction on seeing the first
news about hybrid
flash /
hard drives back in
April 2005 was
skepticism.
I didn't think that a flash / magnetic platter hybrid would
be a good investment for users in either desktop systems or servers.
- in single flash hybrid drive installations such as desktops or notebooks -
the theoretical speedup benefit actually depended on how well Microsoft's Vista
supported this function and whether there was enough free
RAM.
The marginal
benefits delivered by first generation products are (in my view) so small that
if you don't carefully measure the speedup - with
storage analyzers - you
wouldn't notice any speedup at all.
- in multiple flash hybrid drive installations - such as a
RAID system - there is an
overwhelming cost, performance and reliability benefit in using vanilla
hard disks and / or
vanilla SSDs compared to
using hybrids.
Storage
analysts have published various reports which support a cautious view about
the market. (You can see summaries of these in the news column on the left.)
You
have to be cautious about placing too much weight on storage soothsayers'
reports. As in the story about the emperor's clothes - many analysts are
inhibited from saying that a new wardrobe (or market segment) is a complete
waste of space - or invisible. That's because flattery works better in the
courtier's business model.
I thought that was the end of the hybrid
storage drive matter and let it rest.
For several years I didn't even
create a separate page for this subject. Instead I slotted news and vendor
listings about hybrid disks in the
main hard disk page.
My reasoning was that - just as there isn't a need for a separate
listing of disks which have cache memory or buffers (they all do) - there
shouldn't be a need for a standalone flash-HDD hybrid page either. If successful
it would become part of the mainstream HDD market - if not - then I hadn't
wasted too much of my valuable time on it. It would
go away.
I
like to think that I'm quick and mostly right when it comes to recognising
storage trends that matter. And when I've made my mind up that something isn't
in that charmed category - I'm stubborn enough to persist in my prediction
that it's doomed. I was busy enough with other things that really mattered to
readers during
these years. Editing the storage
news page gives me good visibility of emerging themes (and a good safety net
- because I can see how popular stories are with readers).
In
January 2007
Dynamic Network Factory launched a RAM hybrid disk.
I still missed the
subtle difference (between a RAM-HDD hybrid and a flash-HDD) and it was nearly
a year later when I looked in detail at another RAM hybrid - the Platinum
HDD from DTS - that I realised the important differences. I was wrong to
lump all hybrid drives together. The fact that I hadn't lumped them anywhere in
the world wide web wasn't the point. They were marooned on a remote island in
my brain which even the sharks hardly ever swam by.
Forget
everything you know about flash hybrid drives!
They rely on
software from the OS to operate. No OS support (or poorly written software)
means that even the minimal benefit you might get from such a product takes a
powerful set of reading glassses to spot the difference.
The
Platinum HDD in contrast - is a self
contained drive which appears to the OS just like a hard drive. All the clever
caching stuff goes on inside. In fact architecturally it's identical to a
depopulated RAM SSD.
RAM SSDs (unlike flash SSDs) have symmetric read / write IOPS. That
means you get more predictable speedups in a wider range of applications than
with flash.
The Platinum HDD gives you the same kind of results you might see if
you coupled a small capacity RAM SSD to a traditional hard disk based
RAID system. You can buy
it with variable ratios of RAM to hard disk - and the performance is scalable if
you put the Platinum devices in a RAID.
If you're lucky enough to have
the right kind of application it should be easier to install and get results
with the Platinum HDD than either using a
flash SSD or RAM
SSD alongside a hard disk
RAID, and it should cost less too. But you'll need to test the device in your
environment to be sure.
As the ratio of RAM to magnetic storage in RAM
hybrids grows - they could become a very useful tool for systems integrators who
need more IOPS than is available from traditional solutions.
But
that's not the end of the story when it comes to hybrids.
If the RAM
HDD hybrids achieve enough market momentum I predict that will lead to an
entirely new class of hybdrid drive - the RAM-flash Hybrid.
The first
commercial product in that class was the
RamSan-500 launched by
Texas Memory Systems
in September 2007. Although that was a 4U
rackmount SSD - there's
no technical reason why that architectural concept couldn't be put to good use
in a 3.5" form factor
too.
We'll track the exciting developments in the flash-RAM-HDD hybrid
market as usual in our main storage
news page. |
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