Stuff The Internet Says On Scalability For February 28th, 2014

Hey, it's HighScalability time:

  • Quotable Quotes:
    • @ML_Hipster: A machine learning researcher, a crypto-currency expert, and an Erlang programmer walk into a bar. Facebook buys the bar for $27 billion.
    • OH: Network effects don't happen on toll roads.
    • Benedict Evans: Google is a vast machine learning engine... and it spent 10-15 years building that learning engine and feeding it data.
  • Mining Experiment: Running 600 Servers for a Year Yields 0.4 Bitcoin. Yes, this is a far superior way of doing things. Chew up the commons for marginal gain. It's like old times.
  • Game designers, forget the sardines and go hunt some whale. Swrve found: half of free-to-play games’ in-app purchases came from 0.15 percent of players. Only 1.5 percent of players of games in the Swrve network spent any money at all.
  • Google has a beta version of their cloud pricing calculator. The interface is a little funky with separate "Add to Estimate" sections, but the prices look good. 5 servers, with 2 cores, 7.5GB RAM, 24x7, 3TB storage, 100 million IOPS, 1TB snapshot storage, 1TB light Cloud SQL operations, 4TB cloud storage, all for $1,559.24 a month.
  • So scalability doesn't matter? After the WhatsApp acquisition here's a tweet from Telegram Messenger: 4 million users joined Telegram within the last 18 hours. We're doing our best, but the service is getting unstable due to high'll take some time to transport and install the new equipment.
  • Maybe content can make money rather than being cheap commodity chum for aggregators. Financial Times’ CTO John O’Donovan: We make more money from our content than from advertising which is a really interesting shift – we are pushing boundaries in terms of how we are getting our content into these different services and platforms.

Don't miss all that the Internet has to say on Scalability, click below and become eventually consistent with all scalability knowledge...

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The WhatsApp Architecture Facebook Bought For $19 Billion

Rick Reed in an upcoming talk in March titled That's 'Billion' with a 'B': Scaling to the next level at WhatsApp reveals some eye popping WhatsApp stats:

What has hundreds of nodes, thousands of cores, hundreds of terabytes of RAM, and hopes to serve the billions of smartphones that will soon be a reality around the globe? The Erlang/FreeBSD-based server infrastructure at WhatsApp. We've faced many challenges in meeting the ever-growing demand for our messaging services, but as we continue to push the envelope on size (>8000 cores) and speed (>70M Erlang messages per second) of our serving system.

But since we don’t have that talk yet, let’s take a look at a talk Rick Reed gave two years ago on WhatsApp: Scaling to Millions of Simultaneous Connections.

Having built a high performance messaging bus in C++ while at Yahoo, Rick Reed is not new to the world of high scalability architectures. The founders are also ex-Yahoo guys with not a little experience scaling systems. So WhatsApp comes by their scaling prowess honestly. And since they have a Big Hairy Audacious of Goal of being on every smartphone in the world, which could be as many as 5 billion phones in a few years, they’ll need to make the most of that experience.

Before we get to the facts, let’s digress for a moment on this absolutely fascinating conundrum: How can WhatsApp possibly be worth $19 billion to Facebook?

As a programmer if you ask me if WhatsApp is worth that much I’ll answer expletive no! It’s just sending stuff over a network. Get real. But I’m also the guy that thought we don’t need blogging platforms because how hard is it to remote login to your own server, edit the index.html file with vi, then write your post in HTML? It has taken quite a while for me to realize it’s not the code stupid, it’s getting all those users to love and use your product that is the hard part. You can’t buy love

What is it that makes WhatsApp so valuable? The technology? Ignore all those people who say they could write WhatsApp in a week with PHP. That’s simply not true. It is as we’ll see pretty cool technology. But certainly Facebook has sufficient chops to build WhatsApp if they wished.

Let’s look at features. We know WhatsApp is a no gimmicks (no ads, no gimmicks, no games) product with loyal users from across the world. It offers free texting in a cruel world where SMS charges can be abusive. As a sheltered American it has surprised me the most to see how many real people use WhatsApp to really stay in touch with family and friends. So when you get on WhatsApp it’s likely people you know are already on it, since everyone has a phone, which mitigates the empty social network problem. It is aggressively cross platform so everyone you know can use it and it will just work. It “just works” is a phrase often used. It is full featured (shared locations, video, audio, pictures, push-to-talk, voice-messages and photos, read receipt, group-chats, send messages via WiFi, and all can be done regardless of whether the recipient is online or not). It handles the display of native languages well. And using your cell number as identity and your contacts list as a social graph is diabolically simple. There’s no email verification, username and password, and no credit card number required. So it just works.

All impressive, but that can’t be worth $19 billion. Other products can compete on features.

Google wanted it is a possible reason. It’s a threat. It’s for the .99 cents a user. Facebook is just desperate. It’s for your phone book. It’s for the meta-data (even though WhatsApp keeps none).

It’s for the 450 million active users, with a user based growing at one million users a day, with a potential for a billion users. Facebook needs WhatApp for its next billion users. Certainly that must be part if it. And a cost of about $40 a user doesn’t seem unreasonable, especially with the bulk paid out in stock.  Facebook acquired Instagram for about $30 per user. A Twitter user is worth $110.

Benedict Evans makes a great case that Mobile is a 1+ trillion dollar business, WhatsApp is disrupting the SMS part of this industry, which globally has over $100 billion in revenue, by sending 18 billion SMS messages a day when the global SMS system only sends 20 billion SMS messages a day.  With a fundamental change in the transition from PCs to nearly universal smartphone adoption, the size of the opportunity is a much larger addressable market than where Facebook normally plays.

But Facebook has promised no ads and no interference, so where’s the win?

There’s the interesting development of business use over mobile. WhatsApp is used to create group conversations for project teams and venture capitalists carry out deal flow conversations over WhatsApp.

Instagram is used in Kuwait to sell sheep.

WeChat, a WhatsApp competitor, launched a taxi-cab hailing service in January. In the first month 21 million cabs were hailed.

With the future of e-commerce looking like it will be funneled through mobile messaging apps, it must be an e-commerce play?

It’s not just businesses using WhatsApp for applications that were once on the desktop or on the web. Police officers in Spain use WhatsApp to catch criminals. People in Italy use it to organize basketball games.

Commerce and other applications are jumping on to mobile for obvious reasons. Everyone has mobile and these messaging applications are powerful, free, and cheap to use. No longer do you need a desktop or a web application to get things done. A lot of functionality can be overlayed on a messaging app.

So messaging is a threat to Google and Facebook. The desktop is dead. The web is dying. Messaging + mobile is an entire ecosystem that sidesteps their channel.

Facebook needs to get into this market or become irrelevant?

With the move to mobile we are seeing deportalization of Facebook. The desktop web interface for Facebook is a portal style interface providing access to all the features made available by the backend. It’s big, complicated, and creaky. Who really loves the Facebook UI?

When Facebook moved to mobile they tried the portal approach and it didn’t work. So they are going with a strategy of smaller, more focussed, purpose built apps. Mobile first! There’s only so much you can do on a small screen. On mobile it’s easier to go find a special app than it is to find a menu buried deep within a complicated portal style application.

But Facebook is going one step further. They are not only creating purpose built apps, they are providing multiple competing apps that provide similar functionality and these apps may not even share a backend infrastructure. We see this with Messenger and WhatsApp, Instagram and Facebook’s photo app. Paper is an alternate interface to Facebook that provides very limited functionality, but it does what it does very well.

Conway's law may be operating here. The idea that “organizations which design systems ... are constrained to produce designs which are copies of the communication structures of these organizations.” With a monolithic backend infrastructure we get a Borg-like portal design. The move to mobile frees the organization from this way of thinking. If apps can be built that provide a view of just a slice of the Facebook infrastructure then apps can be built that don’t use Facebook’s infrastructure at all. And if they don't need Facebook's infrastructure then they are free not to be built by Facebook at all. So exactly what is Facebook then?

Facebook CEO Mark Zuckerberg has his own take, saying in a keynote presentation at the Mobile World Congress that Facebook's acquisition of WhatsApp was closely related to the vision:

The idea is to develop a group of basic internet services that would be free of charge to use — “a 911 for the internet." These could be a social networking service like Facebook, a messaging service, maybe search and other things like weather. Providing a bundle of these free of charge to users will work like a gateway drug of sorts — users who may be able to afford data services and phones these days just don’t see the point of why they would pay for those data services. This would give them some context for why they are important, and that will lead them to paying for more services like this — or so the hope goes.

This is the long play, which is a game that having a huge reservoir of valuable stock allows you to play. 

Have we reached a conclusion? I don’t think so. It’s such a stunning dollar amount with such tenuous apparent immediate rewards, that the long term play explanation actually does make some sense. We are still in the very early days of mobile. Nobody knows what the future will look like, so it pays not try to force the future to look like your past. Facebook seems to be doing just that.

But enough of this. How do you support 450 million active users with only 32 engineers? Let’s find out...

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Peter Norvig's 9 Master Steps to Improving a Program


Inspired by a xkcd comic, Peter Norvig, Director of Research at Google and all around interesting and nice guy, has created an above par code kata involving a regex program that demonstrates the core inner loop of many successful systems profiled on HighScalability.

The original code is at xkcd 1313: Regex Golf, which comes up with an algorithm to find a short regex that matches the winners and not the losers from two arbitrary lists. The Python code is readable, the process is TDDish, and the problem, which sounds simple, but soon explodes into regex weirdness, as does most regex code. If you find regular expressions confusing you'll definitely benefit from Peter's deliberate strategy for finding a regex.

The post demonstrating the iterated improvement of the program is at xkcd 1313: Regex Golf (Part 2: Infinite Problems). As with most first solutions it wasn't optimal. To improve the program Peter recommends the following steps:

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Stuff The Internet Says On Scalability For February 21st, 2014

Hey, it's HighScalability time (a particularly bountiful week):

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Planetary-Scale Computing Architectures for Electronic Trading and How Algorithms Shape Our World

Algorithms are moving out of the Platonic realm and are becoming dynamic first class players in real life. We've seen corporations become people. Algorithms will likely also follow that path to agency.

Kevin Slavin in his intriguing TED talk: How Algorithms Shape Our World, gives many and varied examples of how algorithms have penetrated RL. 

One of his most interesting examples is from a highly technical paper on Relativistic statistical arbitrage, which says to make money on markets you have to be where the people are, the red dots (on the diagram below), which means you have to put servers where the blue dots are, many of which are in the ocean. Here's the diagram from the paper:

Mr. Slavin neatly sums this up by saying:

And it's not the money that's so interesting actually. It's what the money motivates, that we're actually terraforming the Earth itself with this kind of algorithmic efficiency. And in that light, you go back and you look at Michael Najjar's photographs, and you realize that they're not metaphor, they're prophecy. They're prophecy for the kind of seismic, terrestrial effects of the math that we're making. And the landscape was always made by this sort of weird, uneasy collaboration between nature and man. But now there's this third co-evolutionary force: algorithms -- the Boston Shuffler, the Carnival. And we will have to understand those as nature, and in a way, they are.

The introduction to the paper spells out why this is so:

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Sponsored Post: Couchbase, Tokutek, Logentries, Booking, Apple, MongoDB, BlueStripe, AiScaler, Aerospike, LogicMonitor, AppDynamics, ManageEngine, Site24x7  

Who's Hiring?

  • Apple is hiring for multiple positions. Imagine what you could do here. At Apple, great ideas have a way of becoming great products, services, and customer experiences very quickly.
    • Sr Software Engineer. The Emerging Technology team is looking for a highly motivated, detail-oriented, energetic individual with experience in a variety of big data technologies. You will be part of a fast growing, cohesive team with many exciting responsibilities related to Big Data. Please apply here.
    • C++ Senior Developer and Architect- Maps. The Maps Team is looking for a senior developer and architect to support and grow some of the core backend services that support Apple Map's Front End Services. Please apply here.  
    • Senior Engineer. We are looking for a team player with focus on designing and developing WWDR’s web-based applications. The successful candidate must have the ability to take minimal business requirements and work pro-actively with cross functional teams to obtain clear objectives that drive projects forward to completion. Please apply here.
    • Software Engineer. We are looking for a team player with focus on designing and developing WWDR’s web-based applications. The successful candidate must have the ability to take minimal business requirements and work pro-actively with cross functional teams to obtain clear objectives that drive projects forward to completion. Please apply here.
    • Quality Assurance Engineer. The iOS Systems team is looking for a Quality Assurance engineer. In this role you will be expected to work hand-in-hand with the software engineering team to find and diagnose software defects. Please apply here.

  • We need awesome people @ - We want YOU! Come design next
    generation interfaces, solve critical scalability problems, and hack on one of the largest Perl codebases. Apply:

  • UI EngineerAppDynamics, founded in 2008 and lead by proven innovators, is looking for a passionate UI Engineer to design, architect, and develop our their user interface using the latest web and mobile technologies. Make the impossible possible and the hard easy. Apply here.

  • Software Engineer - Infrastructure & Big DataAppDynamics, leader in next generation solutions for managing modern, distributed, and extremely complex applications residing in both the cloud and the data center, is looking for a Software Engineers (All-Levels) to design and develop scalable software written in Java and MySQL for backend component of software that manages application architectures. Apply here.

Fun and Informative Events

  • Which MongoDB Distribution Should You Use? AOL Benchmark Results - TokuMX vs. MongoDB. March 5th at 1pm ET. It may be easy to choose a NoSQL database, but do you know which distribution is best for you? Which will perform better? Which will scale further? Look before you leap.  Register now.

  • Aerospike Webinar: “Getting the Most out of Your Flash/SSDs”. Tune in to Aerospike's latest webinar, “Getting the Most Out of your Flash/SSDs” at 10am PST Tuesday, Feb. 18 to learn how to select, test and prepare your drives for maximum database performance. Register now. 

Cool Products and Services

  • As one of the fastest growing VoIP services in the world Viber has replaced MongoDB with Couchbase Server, supporting 100,000+ operations per second in the short term and 1,000,000+ operations per second in the long term for their third generation architecture.  See the full story on the Viber switch.

  • Log management made easy with Logentries Billions of log events analyzed every day to unlock insights from the log data the matters to you. Simply powerful search, tagging, alerts, live tail and more for all of your log data. Automated AWS log collection and analytics, including CloudWatch events. 

  • LogicMonitor is the cloud-based IT performance monitoring solution that enables companies to easily and cost-effectively monitor their entire IT infrastructure stack – storage, servers, networks, applications, virtualization, and websites – from the cloud. No firewall changes needed - start monitoring in only 15 minutes utilizing customized dashboards, trending graphs & alerting.

  • MongoDB Backup Free Usage Tier Announced. We're pleased to introduce the free usage tier to MongoDB Management Service (MMS). MMS Backup provides point-in-time recovery for replica sets and consistent snapshots for sharded systems with minimal performance impact. Start backing up today at

  • BlueStripe FactFinder Express is the ultimate tool for server monitoring and solving performance problems. Monitor URL response times and see if the problem is the application, a back-end call, a disk, or OS resources.

  • aiScaler, aiProtect, aiMobile Application Delivery Controller with integrated Dynamic Site Acceleration, Denial of Service Protection and Mobile Content Management. Cloud deployable. Free instant trial, no sign-up required.

  • ManageEngine Applications Manager : Monitor physical, virtual and Cloud Applications.

  • : Monitor End User Experience from a global monitoring network.

If any of these items interest you there's a full description of each sponsor below. Please click to read more...

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How the Architecture Evolved to 99.999% Availability, 8 Million Visitors Per Day, and 200,000 Requests Per Second

This is a guest post by Dave Hagler Systems Architect at AOL.

The AOL homepages receive more than 8 million visitors per day.  That’s more daily viewers than Good Morning America or the Today Show on television.  Over a billion page views are served each month. has been a major internet destination since 1996, and still has a strong following of loyal users.

The architecture for is in it’s 5th generation.  It has essentially been rebuilt from scratch 5 times over two decades.  The current architecture was designed 6 years ago.  Pieces have been upgraded and new components have been added along the way, but the overall design remains largely intact.  The code, tools, development and deployment processes are highly tuned over 6 years of continual improvement, making the architecture battle tested and very stable.

The engineering team is made up of developers, testers, and operations and totals around 25 people.  The majority are in Dulles, Virginia with a smaller team in Dublin, Ireland.

In general the technology in use are Java, JavaServer Pages, Tomca, Apache, CentOS 5, Git, Jenkins, Selenium, and jQuery.  There are some other technologies which are used outside that stack, but these are the main components.

Design Principles

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Stuff The Internet Says On Scalability For February 14th, 2014

Hey, it's HighScalability time:

  • 5 billion: Number of phone records NSA collects per day; Facebook: 1.23 billion users, 201.6 billion friend connections, 400 billion shared photos, and 7.8 trillion messages sent since the start of 2012.
  • Quotable Quotes:
    • @ShrikanthSS: people repeatedly underestimate the cost of busy waits
    • @mcclure111: Learning today java․net․URL․equals is a blocking operation that hits the network shook me badly. I don't know if I can trust the world now.
    • @hui_kenneth: @randybias: “3 ways 2 be market leader - be 1st, be best, or be cheapest. #AWS was all 3. Now #googlecloud may be best & is the cheapest.”
    • @thijs: The nice thing about Paper is that we can point out to clients that it took 18 experienced designers and developers two years to build.
    • @neil_conway: My guess is that the split between Spanner and F1 is a great example of Conway's Law.
  • How Facebook built the real-time posts search feature of Graph search. It's a big problem: one billion new posts added every day, the posts index contains more than one trillion total posts, comprising hundreds of terabytes of data. 

  • Chartbeat Engineering shares some of their experiences in two excellent articles: Part 1,  Part 2. Lessons: DNS is not a great means of load balancing traffic; Modifying sysctl values from their defaults can be important to ensure reliability; Graphing metrics is your friend;  Through TCP tuning and utilizing AWS Elastic Load Balancer we were able to decrease our response time by 98.5%, decrease our server footprint by 20% on our front end servers;  Enabling cross-zone load balancing got our request count distribution extremely well balanced;  planning to move from the m1.large instance type to the c3.large.  The c3.large is almost 50% cheaper and gives us more compute units which in turn yields slightly better response times.

  • Creating a resilient organization is a little like getting an allergy shot, you have to ingest a little of what ails you to boost your immune system. That's the idea behind DiRT, Disaster Recovery Testing event. In Weathering the Unexpected is the story of how far Google goes to improve their corporate immune system with disaster scenarios. Disasters can range from a walk-through of a backup restore to a company wide zombie attack simulation. More here and here.

  • 37signals' shows the power of focus by shedding all their products except Basecamp and even renaming themselves to be just Basecamp. A company can can grow wild unless pruned and shaped to let in the maximum amount of sunlight, growing the most and ripest fruit. While a hard prune is common in the orchard, it's not so common in an organization. A very brave move.

  • When I suggested this I was laughed at. So there! Patch Panels in the Sky:A Case for Free-Space Optics in Data Centers: We explore the vision of an all-wireless inter-rack datacenter fabric. 

Don't miss all that the Internet has to say on Scalability, click below and become eventually consistent with all scalability knowledge...

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Snabb Switch - Skip the OS and Get 40 million Requests Per Second in Lua

Snabb Switch - a toolkit for solving novel problems in networking. If you are building a new packet-processing network appliance then you can use Snabb Switch to get the job done more quickly.

Here's a great impassioned overview from erichocean:

Or, you could just avoid the OS altogether:

Our current engineering target is 1 million writes/sec and > 10 million reads/sec on top of an architecture similar to that, on a single box, to our fully transactional, MVCC database (write do not block reads, and vice versa) that runs in the same process (a la SQLite), which we've also merged with our application code and our caching tier, so we're down to—literally—a single process for what would have been at least three separate tiers in a traditional setup.

The result is that we had to move to measuring request latency in microseconds exclusively. The architecture (without additional application-specific processing) supports a wire-to-wire messaging speed of 26 nanoseconds, or approx. 40 million requests per second. And that's written in Lua!

To put that in perspective, that kind of performance is about 1/3 of what you'd need to be able to do to handle Facebook's messaging load (on average, obviously, Facebook bursts higher than the average at times...).

Point being, the OS is just plain out-of-date for how to solve heavy data plane problems efficiently. The disparity between what the OS can do and what the hardware is capable of delivering is off by a few orders of magnitude right now. It's downright ridiculous how much performance we're giving up for supposed "convenience" today.


Paper: Network Stack Specialization for Performance 

In the scalability is specialization department here is an interesting paper presented at HotNets '13 on high performance networking: Network Stack Specialization for Performance.

The idea is generalizing a service so it fits in the kernel comes at a high performance cost. So move TCP into user space.  The result is a web server with ~3.5x the throughput of Nginx "while experiencing low CPU utilization, linear scaling on multicore systems, and saturating current NIC hardware."

Here's a good description of the paper published on Layer 9:

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