news and articles|
the SSD reliability
way to the Petabyte SSD
sudden power loss
enterprise SSD users want?
11 key Symmetries in
all SSD designs
Guide to Enterprise SSDs
directions in rackmount SSDs
Challenges in flash SSD Design
Efficiency - making the
same SSD - with less chips
failures in time and faulty
thinking in SSD reliability analysis
|coming soon - an
incrementally denser rackmount SSD from Nimbus|
25, 2014 - What does a
petabyte of pure
flash enterprise SSD look like?
It depends on who makes it, the
relative speed category
of the storage itself and the user's own preferences for
schemes and associated
the densest (best) level - a petabyte of enterprise SSD can occupy as little as
2U rack space (skyEagle
The upper limit in size depends a lot on the internal
and memory type
- but typically occupies 10x to 20x more physical space than the example I've
On that theme - Nimbus Data today
that in April it will sample the next generation of its own fast
featured SSD systems - the Gemini X - which will provide an incremental 2x
capacity density improvement over the company's previous offering.
Gemini X implements 960TB (raw) unified SSD storage with 100 microseconds
latency (at under 6W / TB) in 24U of rackspace (40GB/s internal bandwidth)
with external connection via 10 dual ports which can be
40Gb Ethernet or
Like most leading vendors -
Nimbus likes to
think that its product are better than some other named competitors.
But all such comparisons are very selective.
ESG reports on clustering Virident's PCIe SSDs
January 23, 2014 - ESG
today published a
report for Virident
/ HGST's FlashMAX
II (PCIe SSDs)
which validated the ability of this product family and its
(vShare ) to be configured for useful operation in an Oracle RAC environment
availability configurations which were clustered via
ESG said performance was good they also commented on some current
limitations of the product suite for this type of application. In particular:-
- the lack of a graphical interface for setup and performance mintoring,, and
- the lack of support for other supported fabrics such as 10GbE (mentioned
in the report as a future option), and PCIe fabric (which was not mentioned at
all in this report).
new blog by PernixData describes the intermediate states of play
for its HA clustered write acceleration SSD cache
November 5, 2013 - In a clustered,
SSD ASAP VM
environment which supports both read and write acceleration it's essential to
know the detailed policies of any products you're considering - to see if the
consequences - on data vulnerability and performance comply with strategies
which are acceptable for your own intended uses.
In a new blog -
Tolerant Write Acceleration by Frank Denneman
Technology Evangelist at PernixData
describes in a rarely seen level of detail the various states which his
company's FVP goes through when it recognizes that a fault has occured in
either server or flash. And the blog describes the temporary consequences - such
as loss of acceleration - which occur until replacement hardware is pulled in
and configured automatically by the system software.
Stating the design
principles of this product - Frank Denneman says - "Data loss needs to be
avoided at all times, therefore the FVP platform is designed from the ground up
to provide data consistency and availability. By replicating write data to
neighboring flash devices data loss caused by host or component failure is
prevented. Due to the clustered nature of the platform FVP is capable to keep
the state between the write data on the source and replica hosts consistent and
reduce the required space to a minimum without taxing the network connection too
SSD ASAPs - auto tiering /
McObject shows in-memory database resilience in NVDIMM
October 9, 2013 - what happens if you pull out the power plug during
intensive in-memory database transactions? For those who don't want to rely on
batteries - but who also need ultimate speed - this is more than just an
Recently on these pages I've been talking a lot
about a new type of
SSDs which are hoping to break into the application space owned by
PCIe SSDs. But another
solution in this area has always been DRAM with power fail features which save
data to flash in the event of
loss. (The only disadvantages being that the memory density and cost are
constrained by the nature of DRAM.)
products include in-memory database software) yesterday
published the results of
benchmarks using AGIGA
Tech's NVDIMM in which
they did some unthinkable things which you would never wish to try out for
yourself - like rebooting the server while it was running... The result?
Everything was OK.
"The idea that there must be a tradeoff
between performance and persistence/durability has become so ingrained in the
database field that it is rarely questioned. This test shows that mission
critical applications needn't accept latency as the price for recoverability.
Developers working in a variety of application categories will view this as a
breakthrough" said Steve Graves,
Here's a quote from the whitepaper -
Persistence, Without The Performance Penalty (pdf) - "In these tests
eXtremeDB's inserts and updates with AGIGA's NVDIMM for main memory storage
were 2x as fast as using the same IMDS with transaction logging, and
approximately 5x faster for database updates (and this with the
transaction log stored on RAM-disk, a solution that is (even) faster than
storing the log on an SSD). The possibility of gaining so much speed while
giving up nothing in terms of data durability or recoverability makes the IMDS
with NVDIMM combination impossible to ignore in many application categories,
including capital markets, telecom/networking, aerospace and industrial
Editor's comments:- last year McObject
published a paper showing the benefits of using PCIe SSDs for the transaction
log too. They seem to have all angles covered for mission critical ultrafast
databases that can be squeezed into memory.
another $150 million for Pure Storage
fastest growing storage company in history"
29, 2013 - Pure
Storage today -announced
that it has closed an oversubscribed $150 million Series E funding round with
institutional investors which brings the company's total capital raise to $245
million. The company has shipped hundreds of units of its FlashArrays
(fast-enough rackmount SSDs) to a diverse global customer base and claims
it's one of the fastest growing storage companies in the industry's history.
Editor's comments:- in 2001 I started an annual series which
listed the fastest growing
storage companies - based on revenue growth. I ended the series in 2007/8
when the credit crunch kicked in. But you can still see many of the archived
In the last year of the series there were 3 storage
companies which reported over 300% year on year revenue growth. Today Pure
Storage is hinting that its year on year revenue growth is north of 400%.
VCs and SSDs
OCZ ships PCIe SSD based SQL accelerator
July 23, 2013 - OCZ
the general availability of its
Accelerator - an SSD
ASAP appliance - delivered as a PCIe SSD (600GB, 800GB or 1.6TB) and
bundled software - which optimizes caching of SQL Server data in Windows
environments - and can provide upto 25x faster database performance.
functionality works through Microsoft SQL Server AlwaysOn technology, so that
in the event of planned or unplanned downtime, can continue operations from the
stopping point, retaining all of its data as if no downtime had occurred.
"We believe that the industry is primed for this type of tightly
integrated, plug-and-play use-case acceleration solution..." said Ralph Schmitt,
CEO - OCZ Technology.
Editor's comments:- One of the
differentiators in SSD caching products is the sophistication of their
behavior when viewed from a time basis. This is 1 of the
11 key SSD
symmetries - which I call "age symmetry".
In this respect
- a key feature of ZD-XL SQL Accelerator is its business-rule pre-warming
cache engine and cache warm-up analyzer that monitors SQL Server workloads and
automatically pre-loads the cache in advance of critical, demanding or important
SQL Server jobs. It achieves this by identifying repeated access patterns that
enable DBAs to set periodic time schedules to pre-load the cache.
product won Best of Show Award at an event called Interop in
Violin's new blog on PCIe vs FC SAN SSDs
June 11, 2013 - How much confidence do you have in the
of the SSD system which you're deploying? - And how different are the
reliability costs when you scale
PCIe SSDs compared to
are some of the issues discussed in a new blog by Violin -
Memory: too Array or to Card - written by the company's CTO of Software -
Goldick - who warns that when you're estimating the latency
advantages between different ways of connecting SSDs - "Always be
cognizant that you may just be moving the bottleneck to the software." ...read
Kaminario drops PCIe and turns to SAS to get costs down in new
Editor:- April 18, 2013 - "You don't have to be
an investment bank like JP Morgan to afford our style of fast, scalable high
availability SSD systems any more" - was the key message I got talking to
VP Business Development at Kaminario earlier
this week when discussing with me aspects of the company's newest series of
FC SAN compatible SSD
arrays - the
K2 v4 which was
Phil was referring to the expectation that their products -
which in the first generation were entirely
RAM based SSDs - and
then moved onto RAM / flash hybrids and then mostly pure flash (the flash
components being implemented in the previous generation of K2's by
Fusion-io's PCIe SSDs
- a relationship direction which I suggested in a much earlier briefing
conversation with Kaminario's CEO few years ago BTW ) - had acquired a
reputation of being out of reach pricewise - and not just in a class of their
own for resilience and
of the ways that Kaminario has pulled off the affordability trick is to drop
PCIe SSDs as the internal flash components and use instead
said before that in the enterprise arrays space - "SAS is the new SATA"
- because there are so many companies which have moved into this segment
that there's stiff competition. Unlike the PCIe SSD market -which is mostly sold
on high performance - the SAS market includes a number of vendors who have been
R/W ECC to enable them to use cheap flash to build reliable
Because Kaminario still has a lot of
RAM cache in
its server based architecture - it doesn't need the raw
and performance of
FIO's ioMemory to deliver multi-gigabyte throughput at the rack level. And
another factor is that Fusion-io itself is on course to become a significant
supplier of rackmount SSDs (although not aimed at the same kind of customers.)
Kaminario didn't want to say which SAS product they're using. They
might say later. But it doesn't really matter.
The K2 v4 also
demonstrates that the key IP component in Kaminario's box is SSD software.
When I suggested that future boxes could equally well discard SAS SSDs if
2.5" PCIe SSDs
offered a better set of characteristics - Phil agreed that the company wasn't
tied to any particular internal SSD drive form factor or interface.
has paid Taneja Group
to do some new testing on the performance aspects of simulated hard faults.
These will be very useful for customers - and take the uncertainty out of the
picture - giving hard numbers for various scenarios.
For example - when
running at just under 200K
5GB/s throughput - an entire node (controller) was removed to simulate a fault.
I/O resumed after 23 seconds and performance dropped by less than 15% for 2
minutes before recovering fully.
IBM paper on SSD's data challenges
4, 2012 - I've been browsing the
papers from last week's Server
If you can only read one - it should be this:-
do we handle all the data? (pdf) - by Andy Walls, Distinguished
Engineer, Storage Hardware Chief Architect, IBM.
I won't give
away the plot - because I think you'll enjoy it more if you read it yourself.
But here are a few bullet points which resonated with me.
things - Andy Walls says...
- "90% of all the data in the world today was created in the last 2
the article (pdf)
- "Flash is starting to free up the IO bottleneck - but the bottleneck
is more complicated..."
future SSD capacity
ratios , SSD
are we now with SSD software?
HA Support in Fusion-io's ION SAN kit
2, 2012 - Yesterday - Fusion-io
its new ION software
- which is a toolkit for bulding your own network compatible
SSD rack by
adding some Fusion-io SSD cards and their new software to any leading server.
The concept isn't entirely new - because oems have been doing this
with various different brands of
PCIe SSDs for years
and this is a well
established alternative market segment for PCIe SSDs. What is new - is
that it makes the whole thing much easier.
Fusion-io says this new
software product "delivers breakthrough performance over
iSCSI using standard
protocols." (1 million random IOPs (4kB), 6GB/s throughput and 60
microseconds latency in a 1U rack.)
It also supports fault tolerance
HA support in OCZ's PCIe SSD software
3, 2012 - OCZ
published a white paper today -
MS SQL Server 2012 with OCZ Flash Virtualization (pdf) which describes
the performance of the company's
PCIe SSDs (Z-Drive R4)
caching and virtualization software in this kind of environment.
interesting angle (for me) was in the aspect of
tolerance rather than the 16x VM speedup.
author Allon Cohen
(who has written many thought provoking
explains in this paper - "VXL software has a unique storage virtualization
feature-set that enables transparent mirroring of SQL Server logs between 2
flash cards, thereby assuring that the log files can be accessed with ultra high
performance, while at the same time, are highly available for recovery if
the article (pdf)
SSD FITs & reliability
Editor:- June 20, 2012
-the component level isn't always the best level of abstraction in modeling
enterprise SSD reliability.
Extrapolating from the single SSD
component level can give you a misleading idea - because SSDs are data
recent article on my SSD news
page on this subject started with an email from a reader who knew a lot more
about SSD component reliability than me.
GridIron's SSDs can serve hundreds of concurrent databases
Editor:- May 30, 2012 - GridIron Systems
describes the setup required to exceed 1 million (4kB) IOPS in a 40x MySQL
environment with mirroring - all in a single cabinet (including servers) using
SSD systems (upto 80TB in this configuration), and some 10GbE and 16GbFC
fabric switches in a new
"In large-scale MySQL environments it's not uncommon to see
hundreds or even thousands of database servers," said Dennis Martin,
President of Demartek
(which tested this configuration). "This reference architecture opens a
new, more efficient architectural approach for serving increasing numbers of
users and database queries per cabinet."
Pure Storage unveils new HA deduped array
May 16, 2012 - Pure
a new generation of fast-enough
(100K write IOPS)
HA/FT SSD arrays
today - with upto 100TB compressed capacity - which are clustered around
new article on Enterprise SSD Array Reliability
March 1, 2012 - Objective Analysis
has published an article -Enterprise
Reliability, Solid State Speed (pdf) - which examines the conflicts which
arise from wanting to use SSD for enterprise acceleration - while also
preserving data protection in the event of SSD failure.
and architectures are required - because traditional methods can negatively
impact performance - or - as in the case of RAID - don't always work.
"RAID is configured for
HDDs that fail
infrequently and randomly. SSDs
fail rarely as well, but fail predictably" says the author Jim Handy -
who warns that "SSDs in the same RAID and given similar workloads can be
expected to wear
out at about the same time."
He examines in detail one of the
many new aproaches to high availability enterprise SSD design - that's used in
the article (pdf)
the SSD reliability
availability enterprise SSD directory and
SSD market analysts.
TMS packs 24TB fastest HA eMLC in 1U
February 28, 2012 - I was just getting used to getting the measure of how much
enterprise flash capacity can fit into 1U rackspace - when Texas Memory Systems
changed things yet again by doing even more.
announced a 24TB
system called the
This has similar internal architecture to their 720 which
I discussed with
their CEO Holly Frost last December - but it uses
eMLC instead of
SLC - hence the doubling of the storage density.
TMS today revealed
more about the internal features of their proprietary rackmount SSDs. Their
RamSan-OS has been in continuous development for over 5 years, initially
shipping with the RamSan-500
flash SSD in 2007.
The RamSan-OS is designed from the ground up to run on a cluster of CPU
nodes and FPGAs distributed throughout the RamSan systems.
is still a core differentiator from TMS.
"Many of our competitors
claim they are software companies and that their products are Application
Accelerators. While this may be fundamentally true, all TMS products are 2x
faster than any other Application Accelerators shipping today,"
according to TMS CEO Holly Frost. "It comes down to very simple
technical and business questions: Why put key functions into slow software when
you can speed up these functions in fast hardware?"
consumption is an important part of the
- and to drive this point home TMS say they are happy to supply customers with
a wattmeter so they can compare these new SSDs with competing products.
Huawei Symantec publishes SPC-1 results for Dorado2100 SSD
January 12, 2012 - Huawei
Symantec has published an
Benchmark report (66 pages pdf) for its high availability FC SAN rackmount
SSD - the
A 1 terabyte (approx) usable protected (mirrored) SSD
system (2.4TB raw) delivered over 100K SPC-1 IOPS at a market price of$0.90/SPC-1
here for summary (pdf)
Editor's comments:- these
reports are very technical and the $ per SPC-1 IOPS headline
figures include a lot of detailed factors including 3 years of 4 hour on-site
response warranty etc. But the documents also include market prices for
everything which goes into these calculations. From which we learn that a
2.4TB Dorado2100 SSD system with 16x 8Gbps FC ports costs about $52,000. See
also:- SSD pricing
will new RamSan rattle Violin?
Editor:- December 6,
Texas Memory Systems today
imminent availability of the
- a 4 port (FC/IB) 1U
which provides 10TB of usable 2D (FPGA implemented)
RAID protected and hot
swappable - SLC
capacity with 100/25 microseconds R/W latency (with all protections in
place) delivering 400K IOPS (4KB), 5GB/s throughput - with no single point of
failure (at $20K/TB approx list).
The new SSD uses a
regular RAM cache
flash architecture which in the event of
loss has an ultra reliable battery array which holds up the SSD power for 30
seconds while automatically backing
up all data in flight and translation tables to nonvolatile flash storage. On
power up - the SSD is ready for full speed operation in less than a minute.
at HA tier 1 storage markets - the RamSan-720 consumes only 300-400 W - which
makes it practical for high end users to install nearly 1/2
petabyte of SSD
storage in a single cabinet - without having to worry about the secondary
risks which can arise from high temperature build-ups in such
Editor's comments:- I've
been talking to TMS every month for over 10 years - and I've been writing
about their memory appliances since the early 1990s - so you might think that I
would have run out of things to say by now. When I saw the preliminary specs
for the new RS-720 - the features which jumped out at me were:-
- the low R/W latency for this class of SPOF product. Which is 2x as
good as the next fastest product I know - the 6000 series fron
Violin - and several
times faster than some other tier 1 SSD vendors such as
A few days ago I spoke to
Holly Frost, CEO
and Dan Scheel,
President of Texas Memory Systems about their new SSD, what they think about
what's going on in the SSD market, and the philosophy that steers the design
of their SSDs. In a hour long discussion I learned enough new stuff to write
several new articles. So instead of condensing it down here into a couple of
bullet points - I'm going to give you the benefit of what I learned in a
new article tomorrow called -
talks SSD with Holly Frost."
- the high storage density - over 3x better than
Violin delivers in SLC -
and close to the usable RAIDed capacity that a
Fusion-io 1U server
can deliver in MLC when using Octal.
Going back to my headline - will
new RamSan rattle Violin?
I'm sure that Violin would say that this
simply validates what they are doing (and shipping) already - and that the
enterprise SSD market is big enough for all vendors in this category to
at a healthy clip. It make you wonder how much a company like TMS might be worth
Violin unveils naked cost advantages in reliable SSD arrays
September 27, 2011 -
new models and options in its range of fast
FC SAN rackmount SSDs.
series - designed for high availability applications with no single point
of failure and hot swappable "everything" - provides 12TB SLC, or
22TB MLC usable capacity with 200/600 microseconds mixed latency, 1 million /
500K sustained RAIDed spike free write IOPS, in 3U rackspace at a list price
around $37K / $20K per terabyte.
For less demanding applications (but
still featuring hot swap memory modules) the company has also extended its
to 16TB SLC usable capacity.
Editor's comments:- when I spoke
to Violin's CEO -
Basile about the new 6000 series he was curious about how I would tell
you what's unique about this product and signal whether it's relevant to you or
I said - when it comes to reliability -
you've either got it - or you haven't - and there aren't too many enterprise
SSD systems which have hot-swap everything. That's one of the reasons the
latency looks slow - compared to many other fast SSDs - because the figures
quoted here include the latency of the internal factory built protection
Another angle - I said is your product is an example of
architecture". When I explained what I meant - Don agreed and said
what it means for the customer is
Because when you look at the raw capacity that's lost to over-provisioning
and RAID like protection
and get down to the usable capacity that the customer sees in an MLC rack - say
- then Violin's 6000 delivers about 70% of the raw capacity - versus nearer to
30% in an array of 2.5"
SSDs for example. That confers a 2 to 1 native cost and density
(SSD TB/U) advantage.
I said Violin's density looks good too - compared
say to Kaminario's K2.
also said - that our SSD readers would recognize what was meant by "spike-free"
IOPS - because of various
about this - and because another enterprise flash vendor -
Virident Systems -
had made that one of the
talk about compared to some other flash
PCIe SSD companies. I
knew that in Violin's case that was due to their patented non-blocking write
architecture - which was explained to me when their
products came to market in 2008.
Don said - that inside their
protection array they're actually doing 5x more IOPS than the customer
is seeing outside the box and on the datasheet - and that helps too.
also asked about price - and where they were relative to $30K / TB - which is
the ballpark for this type of product - and you can see where Violin are above.
That's a competitive figure for a no SPOF SSD.
I said that for people
who are serious about enterprise SSDs it's relatively easy to decide what
products you may want to focus in on after just seeing a couple of simple
Don did also mention a comparative write up - about their
SSD versus another so called "tier 1" storage solution - from
EMC. Violin think it
makes them look pretty good - but I can't understand why anyone cares how they
stack up to EMC - who never understood the SSD plot - which is why their (at
one time) prime SSD supplier
STEC has had a bumpy
revenue stream in recent years.
I had one final question for Don -
which wasn't about Violin's new SSD - but about
which had come to my attention while I was googling the company just before
When can we expect to see a picture of a naked man
featured on a
poster ad? - I asked.
He laughed and indicated it wouldn't be
|Overview of PCIe
topologies for enterprise SSDs|
|Editor:- July 17, 2013 - Taking PCIe Out of the
Box - is just one of the many different topologies discussed in a new white
paper about PCIe and enterprise storage from PLX Technology called -
and PCI Express|
market for factory configured HA / FT SSDs|
Zsolt Kerekes ,
editor - January 26,
It's always been relatively easy for users and
systems integrators to configure high availability rackmount SSD systems by
using failover and clustering techniques designed for traditional
FC SAN or
IP SAN storage systems -
so you may ask - why have a different directory page which is focused on factory
designed HA SSDs?
The answer is:-
(performance in the failed vs unfailed state), ease of use, risk, complexity,
Customer designed fault tolerant wrap arounds
inevitably go outside the SSD
controller loop. And because they simply engage data at the host
interface level they incur considerable losses in latency and failure recovery
time compared to systems where the HA fault tolerant architecture has been
designed inside the SSD system - behind the host interface and around the SSD
memory arrays. And customized HA SSD designs can introduce software
complexities and controller configuration issues - because even if the native
SSD systems look like virtual storage - the FT wraparound introduces its own
Anyone who has done a formal hazard
analysis or failure analysis in a critical industry knows that it's all too
easy to think that a particular FT problem has been solved whereas in fact
there are still common modes of failure.
One of the invisible risks of
"configure your own" HA arrays is that the user may incur the cost of
assembling a DIY HA configuration only to discover that when a fault does occur
- their solution became part of the problem instead of solving it. That's
another reason that factory designed HA SSDs are superior. They reduce risk -
due to the fact that they have been designed by people who spent more time
thinking about the problems than you can afford to do yourself.
I've spoken to in the HA SSD market are excited that their products will open up
new businesses - but a particular concern - first voiced to me in November 2011
Basile, CEO of Violin
was that HA SSDs could just get lost amidst a sea of other SSD announcements.
And if you're reading through a bunch of pages which talk about
SSD performance and
see some latency and performance figures for an HA SSD in the wrong context -
you may well think - that's doesn't sound so great - whereas in the context of a
protected performance metric - it may instead be truly amazing.
past 20 years of publishing enterprise buyers guides - I've developed an
instrinct for judging when the market is ready for a new focused directory.
Sometimes I've been too early - but with the memontum in the SSD market and the
number of HA SSD vendors dipping into double digits - I think this is
exactly the right time for a new directory.