Interesting Reading : Oracle’s Java Magazine

One of e-magazines I’ve overlooked is Oracle’s Java Magazine. There is a good amount of interesting content in it. You can look at the current issue and back issues.  Select one of the images below to go to the place you sign up.



One recent example from another edition was an article on Twitter’s move and use of Java:

Look inside >
# performance

Recommended Viewing : NASA’s Curiosity Rover and Its Software

If you are interested in Mars, and I am, I was happy to hear that Curiosity had recently explored and found evidence of past water formations on Mars.  You can listen in some detail to what Curiosity is doing by listening to some of the scientists discuss the finds.


Recently, I read that NASA had upgraded the software on the Mars Rover, Curiosity. This third upgrade since the rover landed extends its capabilities.  You can read an article on this upgrade, here.  The article made me curious about what Curiosity’s software looks like.  I found a very interesting talk on the topic from the HotDep ’12 conference :


Also check out this.  You may also be interested in NASA’s Independent Verification & Validation Facility organization workshop :


An interesting workshop, 2010 Workshop on Spacecraft Flight Software provides more details.



Recommended Viewing : Java 8 Background Videos

Java 8 will be available sometime this coming year. It is worth knowing what is in it. Two videos help with this.

swdevSimon Ritter, a Java Technology Evangelist, at Oracle gave a good overview of what’s in Java 8 that he gave at Devoxx 2013 Conference.  Java 8 is destined to be available later next year.  Simon’s talk provided a view of 55 lesser known features that will be available in Java 8. If you want to enlarge it you can go directly to the Parley’s video by selecting the Parley’s label on the top of the video frame.

Another very good talk on Java 8 from JavaOne 2013 is Mark Reinhold, Chief Architect for the Java Platform group at Oracle :


Recommended Reading : Inter-Thread Communications In Java At The Speed of Light

One of the more interesting articles in a long while on inter-thread communications.  The zingzingarticle covers high-performance inter-thread communications in Java and offers the results of a series of experiments.  From an initial design to the final set of designs there is a huge leap in performance.  Testing various approaches – single producer/single consumer, single producer/two consumers, three producers/single consumer and mixed producers/consumers.  In an addition, he highlights an ultra-high throughput single producer/single consumer able to achieve one and half billion operations/sec with a 1.3 microsecond latency.


It’s worth also pointing out two additional reads (one is a blog, one is an article) :




Recommended Viewing : Flash and OpenStack in the Enterprise – An Accelerating Trend

There is a nice talk about flash storage and OpenStack by Dave Wright, CEO at SolidFire and Roark Hilomen, Distinguished Engineer and Technologist at eBay. In the fairness of full disclosure – I know Roark, a friend and one of eBay’s brightest engineers.  SolidFire and eBay presented at the Samsung Memory Solutions Forum on Tuesday, October 22, 2013 at the Computer History Museum to discuss the rising demand of flash storage and OpenStack within the enterprise. The session, “Flash and OpenStack in the Enterprise: An Accelerating Trend” covered the rapid shift that is occurring in how enterprise IT infrastructure is being deployed and managed within the Next Generation Data Center.

See more here.

Also Samsung Memory Forum 2013 presentations  (PDFs):


gotostorageGo to more posts on storage and flash storage at

KVM Forum 2013 : Presentation PDFs and Videos Available

The recently concluded 2013 KVM Forum has made available sessions You can start by finding the PDFs of keynotes and presentations at the site.


In addition, videos of the sessions have been made available :


Please note that the quality of the video and audio on some of these have issues, however, if you are interested in KVM this may be of interest to you.

Deduplication Fears From Those That Don’t Offer It

[UPDATE : Congratulations to Violin Memory – this past week they finally released a version of deduplication for their OS, and a pretty good one at that. You can read the post below to understand the history involved and the good news of finally getting to this point].

[ This has been updated – see update below.  For more on the new class of flash arrays that fully support deduplication and a full range of storage features, Recommendations for All-Flash Storage Arrays; Aiming Beyond Simply IOPS and Low Latency.]

Sometime ago, I wrote the post and in that article, I pointed out there are places where de-dup fits nicely and, yes, that it is possible to mis-use de-duplication and that companies that don’t offer de-duplication at all (inline or not – as part of their array’s operating environment) don’t even give their customers the choice to use or not use it or for what to use or not use it with.  Recently, Violin Memory’s founder wrote an interesting post pointing to some of the issues he sees with inline de-duplication. This post will offer an alternative view.

We are seeing more interesting articles on de-duplication and data reduction generally.  First, a really well-rounded article (and talk), All-Flash Storage Efficiency Is About More Than De-Duplication, from George Crump, Lead Analyst at StorageSuisse.  In this article he also nicely points to other data reduction technologies.  I especially like that he includes replication – a key enterprise technology that is part of the foundation for disaster recovery.  Also mentioned is thin-provisioning and compression.  All of these are important technologies along with de-duplication.  You can also learn more by listening to the Permabit/StorageSuisse video.


You could be forgiven if you thought that Violin Memory didn’t like de-duplication as a technology since they have been offering articles fearing the worst from using de-duplication  –

  • First, an article from CTO Jonathan Goldick (recently departed from Violin Memory), Thoughts on DDUP and Compression.
  • Second, a cautionary article, Storage Myths: Dedupe for Databases from flashdba, who according to his blog is employed by Violin Memory but his views are clearly his own.  The article attempts to debunk the storage “myth” about dedup for databases.  In it they explain some of the issues with using dedup in conjunction with Oracle.  They conclude that while dedup may be great for use cases like VDI it offers limited benefits in database environments.
  • Finally, the latest de-dup article comes from (founder and CTO) Jon Bennett of Violin Memory who has offered up, admittedly, some edge use-cases where you might not want to use inline de-duplication.  Fair enough.   In Bennett’s article he states that and always-on de-duplication used with databases is not a feature but a bug.  On Twitter, Violin Memory offered the following tweet :

The unwritten subtext in these articles  seems to be a subtle or not-so-subtle argument that, somehow, those that don’t offer or use de-dup – are somehow better off.  The subtlety that not everything is a database is somehow missed here. And more interestingly some of the on-going developments with inline de-dup seem to have been overlooked or gone unmentioned. This suggests a company at a competitive disadvantage.

Unlike, SolidFire, Pure Storage, Nimbus Data, NetApp,Tegile, HP, Hitachi Data Systems, EMC, etc, etc – Violin Memory does not offer de-duplication directly in their array’s VMOS operating system – inline or not – so even if the application that is using the array is for a VDI deployment where de-dup might make perfectly good sense – too bad, you can’t leverage native de-duplication even on the latest Violin Memory’s 6264 with the latest vMOS operating system.   Ouch.

You would think that Jon’s points would have easily demonstrable proof-points in the real world with architectures like Pure Storage or Tegile where inline de-duplication is being consistently used with databases.  Tegile offers some database numbers in their lab tests that I found interesting and excellent (page 12) :


You would also think that this ‘bug’ would kill any chance that companies like Tegile or Pure Storage would have of competing to run Oracle databases.  Obviously the ‘bug’ is  not a ‘bug’ –  if you look at Pure Storage, like other flash/SSD arrays, it has done reasonably well at winning in the database area.  Especially with architectures that leverage de-duplication and compression like those that use Delphix (see here). They have done a  good job of explaining their support of inline de-duplication :


Permabit who licenses their inline deduplication technologies to vendors has recently demonstrated through an inline deduplication benchmark that crossed the one million IOPS barrier with inline dedup on.  Sound familiar ?  Only this benchmark is with deduplication turned on.


It’s not like always-on or inline de-duplication is the only de-dup offering one is forced into providing or like database vendors like Oracle have told you not to use it in conjunction with their database – quite the opposite. Oracle actually offers use cases and best practices for using  de-duplication around their Oracle Databases and have embedded de-dup in their storage hardware. And  vendors, like Nimbus Data, offer de-duplication today on a per LUN basis. So you have a choice and you can have it on or off on a particular LUN.  You can choose to have some LUNS de-duped and other LUNS not de-duped. Personally, I like this type of design – it provides flexibility.

To understand the strangeness of all of this and before we go any further – let’s step backwards in time.  For some time, Violin Memory has been releasing press releases stating that de-duplication was  coming to their vMOS operating system.  Dizzying PR and articles around the Symantec/Violin Memory partnership can be found that suggest as much as 80% reduction in the storage footprint. In its absence they have even developed a partnership with Atlantis for among other things, in-line de-duplication, to target VDI, which according to the press release will make use of in-line de-duplication to provide consistently fast VDI.  Atlantis seems to understand the value of in-line deduplication.


So the open question, given Jon’s recent article and the antipathy toward de-duplication – will there be a vMOS version of dedup that the Symantec partnership was to provide ?

Summary. The very fact that two CTOs at Violin Memory have fixed their sights on the negatives of de-duplication suggests a company in a defensive posture on the issue of de-duplication in general.  All their major competitors have deduplication.  From my perspective, if a company thinks that always-on de-dup is such a menace to society, then simply offer a version of de-duplication that you can turn on and off.  Nimbus Data’s Halo approach to de-duplication seems to me to be very reasonable – it allows you to turn de-duplication on and off on a LUN/filesystem basis. In any case, at the very least, they should offer their customers the opportunity to use deduplication on good-fit use-cases by including it in their array’s operating system.

With larger vendors like EMC, NetApp and Hitachi offering deduplication technologies, and as well, smaller vendors like Nimbus Data, SolidFire, Tegile and others also successfully offering deduplication technologies – Violin Memory has been for some time and is at a competitive disadvantage because of their lack of de-dup.  Instead of arguing against what is a useful technology they simply need to offer a competitive deduplication feature (as they said they would) in vMOS – and let that implementation speak for itself – as all these other vendors have already done.

Update : Violin Memory introduced dedup into their line-up first with the Windows Flash Array but it has been missing in action from their main staple OS, VMOS. Then they offered it in the Concerto 2200 – a hardware appliance solution that includes dedup. However, this is a costly way to get dedup.  And surprise, no longer a dedup critic, Violin Memory actually sponsored an IDC white paper, Why Inline Data Reduction Is Required For Enterprise Flash Arrays. which was ironic at the time because they didn’t offer inline dedup in their standard VMOS operating system.  Most other all-flash array vendors have been and are offering dedup as part of their array’s operating systems.  It’s hard to imagine that this was really their dedup answer – and it wasn’t. With the latest launch their arrays now offer a version of ‘granular’ deduplication. Visit their site to learn more.


gotostorageGo to more posts on storage and flash storage at

Recommended Viewing : The Netflix Cloud and Cassandra

Netflix is doing some amazing things. If you have the service, you know they are dependent on Amazon Web Services but their cloud practices transcend that dependency.  Adrian Cockroft has delivered some really excellent talks explaining how they do what they do.

and also a nice talk on how they moved to Cassandra to do a lot of the heavy lifting.

and he provided another very nice presentation at the Cassandra conference C*2012 about running Cassandra on AWS.

Interesting in the two Cassandra talks he discusses use of SSDs to improve Cassandra performance. He talks about moving from 2 drives (1.7 TB) to 2 SSD volumes (2 TB).  He shows results from a hard disk versus SSD comparison.  Netflix is offering a number of Cassandra-related software as open source, such as Priam (for Cassandra automation), Astyanax (client, front-end into Cassandra) and more (like Aegisthus, Zeno, Chaos Monkey, Zuul, Pythias, etc).  Note that AppDynamics is used throughout these presentations.  One other project I’m aware of is a non-JVM way of getting to the recipes in Astyanax is STAASH.  You can follow all of this on the Netflix technical blog.


Also a post that may be of interest : Some Thoughts on Why We Want To Run Databases on Flash


Recommended Viewing : Apache Cloudstack Collaboration Conference 2013 Videos Available

Anyone interested in Cloudstack, like me, should be interested in the videos from the recently concluded Apache Collaboration Conference in Amsterdam. Like OpenStack, Cloudstack offers a wealth of cloud features in the form of a cloud stack. The presentations from the Cloudstack Collaboration EU 2013 conference have been made available on YouTube :


Recommended Viewing : OpenStack Summit 2013 Videos Now Available

If you are interested in OpenStack, as I am, you will be happy to learn that openstack500from the recently concluded conference, OpenStack has made available  a wealth of video presentations and keynotes available from OpenStack Summit 2013.  This is an incredible collection of knowledge about OpenStack and people and companies involved with it.


Also of interest, you should follow what eBay/PayPal is doing if you are interested in an implementation in-progress.  At the recently concluded OpenStack Summit 2013 in Hong Kong eBay/PayPal did six sessions.