Welcome!

Apache Authors: Liz McMillan, Elizabeth White, Pat Romanski, Janakiram MSV, Gil Allouche

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
SYS-CON Events announced today Telecom Reseller has been named “Media Sponsor” of SYS-CON's 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. Telecom Reseller reports on Unified Communications, UCaaS, BPaaS for enterprise and SMBs. They report extensively on both customer premises based solutions such as IP-PBX as well as cloud based and hosted platforms.
Pulzze Systems was happy to participate in such a premier event and thankful to be receiving the winning investment and global network support from G-Startup Worldwide. It is an exciting time for Pulzze to showcase the effectiveness of innovative technologies and enable them to make the world smarter and better. The reputable contest is held to identify promising startups around the globe that are assured to change the world through their innovative products and disruptive technologies. There w...
With so much going on in this space you could be forgiven for thinking you were always working with yesterday’s technologies. So much change, so quickly. What do you do if you have to build a solution from the ground up that is expected to live in the field for at least 5-10 years? This is the challenge we faced when we looked to refresh our existing 10-year-old custom hardware stack to measure the fullness of trash cans and compactors.
The emerging Internet of Everything creates tremendous new opportunities for customer engagement and business model innovation. However, enterprises must overcome a number of critical challenges to bring these new solutions to market. In his session at @ThingsExpo, Michael Martin, CTO/CIO at nfrastructure, outlined these key challenges and recommended approaches for overcoming them to achieve speed and agility in the design, development and implementation of Internet of Everything solutions wi...
Cloud computing is being adopted in one form or another by 94% of enterprises today. Tens of billions of new devices are being connected to The Internet of Things. And Big Data is driving this bus. An exponential increase is expected in the amount of information being processed, managed, analyzed, and acted upon by enterprise IT. This amazing is not part of some distant future - it is happening today. One report shows a 650% increase in enterprise data by 2020. Other estimates are even higher....
Today we can collect lots and lots of performance data. We build beautiful dashboards and even have fancy query languages to access and transform the data. Still performance data is a secret language only a couple of people understand. The more business becomes digital the more stakeholders are interested in this data including how it relates to business. Some of these people have never used a monitoring tool before. They have a question on their mind like “How is my application doing” but no id...
The 19th International Cloud Expo has announced that its Call for Papers is open. Cloud Expo, to be held November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA, brings together Cloud Computing, Big Data, Internet of Things, DevOps, Digital Transformation, Microservices and WebRTC to one location. With cloud computing driving a higher percentage of enterprise IT budgets every year, it becomes increasingly important to plant your flag in this fast-expanding business opportuni...
Smart Cities are here to stay, but for their promise to be delivered, the data they produce must not be put in new siloes. In his session at @ThingsExpo, Mathias Herberts, Co-founder and CTO of Cityzen Data, will deep dive into best practices that will ensure a successful smart city journey.
SYS-CON Events announced today that 910Telecom will exhibit at the 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. Housed in the classic Denver Gas & Electric Building, 910 15th St., 910Telecom is a carrier-neutral telecom hotel located in the heart of Denver. Adjacent to CenturyLink, AT&T, and Denver Main, 910Telecom offers connectivity to all major carriers, Internet service providers, Internet backbones and ...
Internet of @ThingsExpo, taking place November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA, is co-located with 19th Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry players in the world. The Internet of Things (IoT) is the most profound change in personal and enterprise IT since the creation of the Worldwide Web more than 20 years ago. All major researchers estimate there will be tens of billions devices - comp...
DevOps at Cloud Expo, taking place Nov 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA, is co-located with 19th Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry players in the world. 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 dev...
Data is the fuel that drives the machine learning algorithmic engines and ultimately provides the business value. In his session at Cloud Expo, Ed Featherston, a director and senior enterprise architect at Collaborative Consulting, will discuss the key considerations around quality, volume, timeliness, and pedigree that must be dealt with in order to properly fuel that engine.
There is growing need for data-driven applications and the need for digital platforms to build these apps. In his session at 19th Cloud Expo, Muddu Sudhakar, VP and GM of Security & IoT at Splunk, will cover different PaaS solutions and Big Data platforms that are available to build applications. In addition, AI and machine learning are creating new requirements that developers need in the building of next-gen apps. The next-generation digital platforms have some of the past platform needs a...
19th Cloud Expo, taking place November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA, will feature technical sessions from a rock star conference faculty and the leading industry players in the world. Cloud computing is now being embraced by a majority of enterprises of all sizes. Yesterday's debate about public vs. private has transformed into the reality of hybrid cloud: a recent survey shows that 74% of enterprises have a hybrid cloud strategy. Meanwhile, 94% of enterpri...
Identity is in everything and customers are looking to their providers to ensure the security of their identities, transactions and data. With the increased reliance on cloud-based services, service providers must build security and trust into their offerings, adding value to customers and improving the user experience. Making identity, security and privacy easy for customers provides a unique advantage over the competition.
I wanted to gather all of my Internet of Things (IOT) blogs into a single blog (that I could later use with my University of San Francisco (USF) Big Data “MBA” course). However as I started to pull these blogs together, I realized that my IOT discussion lacked a vision; it lacked an end point towards which an organization could drive their IOT envisioning, proof of value, app dev, data engineering and data science efforts. And I think that the IOT end point is really quite simple…
Personalization has long been the holy grail of marketing. Simply stated, communicate the most relevant offer to the right person and you will increase sales. To achieve this, you must understand the individual. Consequently, digital marketers developed many ways to gather and leverage customer information to deliver targeted experiences. In his session at @ThingsExpo, Lou Casal, Founder and Principal Consultant at Practicala, discussed how the Internet of Things (IoT) has accelerated our abil...
Is the ongoing quest for agility in the data center forcing you to evaluate how to be a part of infrastructure automation efforts? As organizations evolve toward bimodal IT operations, they are embracing new service delivery models and leveraging virtualization to increase infrastructure agility. Therefore, the network must evolve in parallel to become equally agile. Read this essential piece of Gartner research for recommendations on achieving greater agility.
SYS-CON Events announced today that Venafi, the Immune System for the Internet™ and the leading provider of Next Generation Trust Protection, will exhibit at @DevOpsSummit at 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. Venafi is the Immune System for the Internet™ that protects the foundation of all cybersecurity – cryptographic keys and digital certificates – so they can’t be misused by bad guys in attacks...
For basic one-to-one voice or video calling solutions, WebRTC has proven to be a very powerful technology. Although WebRTC’s core functionality is to provide secure, real-time p2p media streaming, leveraging native platform features and server-side components brings up new communication capabilities for web and native mobile applications, allowing for advanced multi-user use cases such as video broadcasting, conferencing, and media recording.