Welcome!

Apache Authors: Carmen Gonzalez, Trevor Parsons, Sematext Blog , Lori MacVittie, AppDynamics Blog

Blog Feed Post

Big Data Needs a Better Network

Earlier this week I had some interesting conversations with @davehusak. Where the conversation started early in the day with a discussion on overlay networks and what network functions are performed where and in what context, later in the afternoon the discussion moved to networking solutions (and specifically Plexxi solutions) for big data applications.

It’s easy to jump to Hadoop or similarly structured cluster computing applications (Spark, Storm, or a long list of others) as the definition of a big data application. With all its simplicity for the overall distribution of work, Hadoop is a fairly tough network problem to solve if you want to do anything more than “throw bandwidth at the problem”. And when you do throw bandwidth at the problem, the extreme burstiness of the traffic will still significantly drag down the performance of the overall solution. And for many, CPU cycles to reduce the data is not the biggest challenge, storage and movement of data throughout a big data cluster is the biggest pain point. Intel has done a fine job providing compute firepower that far outpaces the evolution of network capacity.

The network plays a significant factor in several stages of a Hadoop solution cycle. It starts with chopping the to-be-analyzed data into chunks and distributing it across the datanodes. Hadoop has a notion of a rack and it has some basic intelligence when placing data and jobs that work on that data. By default the data will be replicated 3 times across at least 2 racks, if racks have been defined. The data to be distributed is easily in the 100s of Gigabytes or even Terabytes, so triple that data is being moved throughout the Hadoop cluster to the datanodes.

Once distributed, the actual Map jobs are launched against that data, these are the tasks that take the data and perform a first pass mapping into (in its most basic form) <key, value> tuples. Again here there is an attempt to have jobs work on local data, where local can be defined as local to the server that has that chunk of data or local to the rack, in an attempt to avoid as much cross rack communication as possible. This is based on the assumption that cross rack communication is much more constrained and aggregated and therefore more prone to congestion and packet loss.

Once the mapper jobs complete their task, the results of the mapping exercise is sent to reducers. Reducers take the <key, value> information and essentially tally the results. This transfer is the most taxing part of a Hadoop cycle on the network. Since most Hadoop mapping jobs run the same function on a similar sized dataset, that first set of mappers will all complete their task at about the same time and will all start sending their results to the same set of reducers, creating 1) a lot of traffic and 2) a lot of traffic to the same set of destinations.  Depending on the amount of data, mappers and compute nodes, this cycle repeats (the next set of mapping jobs are fired off) and at the end of each cycle a very significant spike in network traffic appears. At the very end, all results are brought together for one last spike in traffic. Each one of these network events is a source of significant congestion.

Many variables contribute to the overall performance of the Hadoop solution. What is the relationship between the chunks of data and the amount of servers and jobs? How many reducers are used? Where are the reducers in relation to the mappers? Is the Map function compute heavy or I/O heavy? How aggressive is the speculative scheduling that allows the same data to be worked on by multiple mappers?

With that many variables that can be tuned, and with so many variables different from one analysis to the next, it is hard to imagine that a single network design or implementation provides the best supporting infrastructure. There are assumptions in Hadoop placement of data and jobs that can easily be altered. The basic concept of a rack can easily expanded into a multi layer locality definition. With the right tools in the network, the definition of a rack, or even the locality and closeness of nodes in a cluster or virtual cluster can be adjusted according to the analysis to be completed.

We tend to give our applications variables to tune its performance based on what the network provides. It is time that the network adjusts itself based on the application needs. In a clustered application like Hadoop, there is lots of knowledge and even some predictability of network traffic. Wouldn’t that make for a great opportunity to infuse the network with some of that knowledge and have it morph itself to provide the best possible service? And Hadoop is not unique, cluster compute framework almost all carefully track placement of data and compute jobs, which makes them all great candidates to share some of that information with a smart network.

There are far simpler big data needs and applications that can and should be supported by flexible networks. Storage networks are still often separated from data networks for performance reasons and fear of interference. If you could actually separate the various types of data with logically or even physically different paths in the same network, would you still?

 

[Today's fun fact: An MLB baseball lasts on average 7 pitches. A google search asking how many baseballs are used in a single MLB season returns several pages worth of different answers. They must all be correct, it's on the Internet afterall.]

The post Big Data Needs a Better Network appeared first on Plexxi.

Read the original blog entry...

More Stories By Marten Terpstra

Marten Terpstra is a Product Management Director at Plexxi Inc. Marten has extensive knowledge of the architecture, design, deployment and management of enterprise and carrier networks.

@ThingsExpo Stories
"BSQUARE is in the business of selling software solutions for smart connected devices. It's obvious that IoT has moved from being a technology to being a fundamental part of business, and in the last 18 months people have said let's figure out how to do it and let's put some focus on it, " explained Dave Wagstaff, VP & Chief Architect, at BSQUARE Corporation, in this SYS-CON.tv interview at @ThingsExpo, held Nov 4-6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
The major cloud platforms defy a simple, side-by-side analysis. Each of the major IaaS public-cloud platforms offers their own unique strengths and functionality. Options for on-site private cloud are diverse as well, and must be designed and deployed while taking existing legacy architecture and infrastructure into account. Then the reality is that most enterprises are embarking on a hybrid cloud strategy and programs. In this Power Panel at 15th Cloud Expo (http://www.CloudComputingExpo.com), moderated by Ashar Baig, Research Director, Cloud, at Gigaom Research, Nate Gordon, Director of T...
SYS-CON Events announced today that IDenticard will exhibit at SYS-CON's 16th International Cloud Expo®, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. IDenticard™ is the security division of Brady Corp (NYSE: BRC), a $1.5 billion manufacturer of identification products. We have small-company values with the strength and stability of a major corporation. IDenticard offers local sales, support and service to our customers across the United States and Canada. Our partner network encompasses some 300 of the world's leading systems integrators and security s...
SYS-CON Events announced today that Windstream, a leading provider of advanced network and cloud communications, has been named “Silver Sponsor” of SYS-CON's 16th International Cloud Expo®, which will take place on June 9–11, 2015, at the Javits Center in New York, NY. Windstream (Nasdaq: WIN), a FORTUNE 500 and S&P 500 company, is a leading provider of advanced network communications, including cloud computing and managed services, to businesses nationwide. The company also offers broadband, phone and digital TV services to consumers primarily in rural areas.

ARMONK, N.Y., Nov. 20, 2014 /PRNewswire/ --  IBM (NYSE: IBM) today announced that it is bringing a greater level of control, security and flexibility to cloud-based application development and delivery with a single-tenant version of Bluemix, IBM's platform-as-a-service. The new platform enables developers to build ap...

The BPM world is going through some evolution or changes where traditional business process management solutions really have nowhere to go in terms of development of the road map. In this demo at 15th Cloud Expo, Kyle Hansen, Director of Professional Services at AgilePoint, shows AgilePoint’s unique approach to dealing with this market circumstance by developing a rapid application composition or development framework.
The Internet of Things is not new. Historically, smart businesses have used its basic concept of leveraging data to drive better decision making and have capitalized on those insights to realize additional revenue opportunities. So, what has changed to make the Internet of Things one of the hottest topics in tech? In his session at @ThingsExpo, Chris Gray, Director, Embedded and Internet of Things, discussed the underlying factors that are driving the economics of intelligent systems. Discover how hardware commoditization, the ubiquitous nature of connectivity, and the emergence of Big Data a...
“In the past year we've seen a lot of stabilization of WebRTC. You can now use it in production with a far greater degree of certainty. A lot of the real developments in the past year have been in things like the data channel, which will enable a whole new type of application," explained Peter Dunkley, Technical Director at Acision, in this SYS-CON.tv interview at @ThingsExpo, held Nov 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
DevOps Summit 2015 New York, co-located with the 16th International Cloud Expo - to be held June 9-11, 2015, at the Javits Center in New York City, NY - announces that it is now accepting Keynote Proposals. The widespread success of cloud computing is driving the DevOps revolution in enterprise IT. Now as never before, development teams must communicate and collaborate in a dynamic, 24/7/365 environment. There is no time to wait for long development cycles that produce software that is obsolete at launch. DevOps may be disruptive, but it is essential.
"People are a lot more knowledgeable about APIs now. There are two types of people who work with APIs - IT people who want to use APIs for something internal and the product managers who want to do something outside APIs for people to connect to them," explained Roberto Medrano, Executive Vice President at SOA Software, in this SYS-CON.tv interview at Cloud Expo, held Nov 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
Nigeria has the largest economy in Africa, at more than US$500 billion, and ranks 23rd in the world. A recent re-evaluation of Nigeria's true economic size doubled the previous estimate, and brought it well ahead of South Africa, which is a member (unlike Nigeria) of the G20 club for political as well as economic reasons. Nigeria's economy can be said to be quite diverse from one point of view, but heavily dependent on oil and gas at the same time. Oil and natural gas account for about 15% of Nigera's overall economy, but traditionally represent more than 90% of the country's exports and as...
The Internet of Things is a misnomer. That implies that everything is on the Internet, and that simply should not be - especially for things that are blurring the line between medical devices that stimulate like a pacemaker and quantified self-sensors like a pedometer or pulse tracker. The mesh of things that we manage must be segmented into zones of trust for sensing data, transmitting data, receiving command and control administrative changes, and peer-to-peer mesh messaging. In his session at @ThingsExpo, Ryan Bagnulo, Solution Architect / Software Engineer at SOA Software, focused on desi...
"At our booth we are showing how to provide trust in the Internet of Things. Trust is where everything starts to become secure and trustworthy. Now with the scaling of the Internet of Things it becomes an interesting question – I've heard numbers from 200 billion devices next year up to a trillion in the next 10 to 15 years," explained Johannes Lintzen, Vice President of Sales at Utimaco, in this SYS-CON.tv interview at @ThingsExpo, held Nov 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
"For over 25 years we have been working with a lot of enterprise customers and we have seen how companies create applications. And now that we have moved to cloud computing, mobile, social and the Internet of Things, we see that the market needs a new way of creating applications," stated Jesse Shiah, CEO, President and Co-Founder of AgilePoint Inc., in this SYS-CON.tv interview at 15th Cloud Expo, held Nov 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
SYS-CON Events announced today that Gridstore™, the leader in hyper-converged infrastructure purpose-built to optimize Microsoft workloads, will exhibit at SYS-CON's 16th International Cloud Expo®, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. Gridstore™ is the leader in hyper-converged infrastructure purpose-built for Microsoft workloads and designed to accelerate applications in virtualized environments. Gridstore’s hyper-converged infrastructure is the industry’s first all flash version of HyperConverged Appliances that include both compute and storag...
Today’s enterprise is being driven by disruptive competitive and human capital requirements to provide enterprise application access through not only desktops, but also mobile devices. To retrofit existing programs across all these devices using traditional programming methods is very costly and time consuming – often prohibitively so. In his session at @ThingsExpo, Jesse Shiah, CEO, President, and Co-Founder of AgilePoint Inc., discussed how you can create applications that run on all mobile devices as well as laptops and desktops using a visual drag-and-drop application – and eForms-buildi...
We certainly live in interesting technological times. And no more interesting than the current competing IoT standards for connectivity. Various standards bodies, approaches, and ecosystems are vying for mindshare and positioning for a competitive edge. It is clear that when the dust settles, we will have new protocols, evolved protocols, that will change the way we interact with devices and infrastructure. We will also have evolved web protocols, like HTTP/2, that will be changing the very core of our infrastructures. At the same time, we have old approaches made new again like micro-services...
Code Halos - aka "digital fingerprints" - are the key organizing principle to understand a) how dumb things become smart and b) how to monetize this dynamic. In his session at @ThingsExpo, Robert Brown, AVP, Center for the Future of Work at Cognizant Technology Solutions, outlined research, analysis and recommendations from his recently published book on this phenomena on the way leading edge organizations like GE and Disney are unlocking the Internet of Things opportunity and what steps your organization should be taking to position itself for the next platform of digital competition.
The 3rd International Internet of @ThingsExpo, co-located with the 16th International Cloud Expo - to be held June 9-11, 2015, at the Javits Center in New York City, NY - announces that its Call for Papers is now open. The Internet of Things (IoT) is the biggest idea since the creation of the Worldwide Web more than 20 years ago.
As the Internet of Things unfolds, mobile and wearable devices are blurring the line between physical and digital, integrating ever more closely with our interests, our routines, our daily lives. Contextual computing and smart, sensor-equipped spaces bring the potential to walk through a world that recognizes us and responds accordingly. We become continuous transmitters and receivers of data. In his session at @ThingsExpo, Andrew Bolwell, Director of Innovation for HP's Printing and Personal Systems Group, discussed how key attributes of mobile technology – touch input, sensors, social, and ...