Hot Scalability Links For Sep 17, 2010

  • Disqus - Scaling the Worlds Largest Django App. Interesting overview of a commenting system with 75 million comments and 250 million visitors. Lots of good details on how they partition their database, testing, continuous integration, feature switches, caching, delayed signals, and more.
  • Things I learnt tracking a billion events in 24 hours: Know your host, Scaling isn't just servers, My servers need to talk to me more, Kill switches for users, What you don't know is the problem, Don't mix server roles, Know your most important users outside of your site.
  • Tweets of Gold:
    • georgebarnett: I read High Scalability for useful articles about large scaling. Sadly though, nothing useful ever shows up. #NoLongerBothering
    • northscale: wow that is fast! :) RT @cgoldberg: was just running > 100k ops/sec against my 2-node #Membase cluster... zazooom #nosql
    • turbofunctor: The root of many (horizontal) scalability problems is an application level access to a writable filesystem. (Thus, #appengine.)
    • gwenshap: is like Vogue for IT operations. Map-reduce is so last season.

    Click to read more ...


Strategy: Buy New, Don't Fix the Old

This strategy is from the Large Hadron Collider project:
Improvements in performance per Watt have caused CERN to no longer sign hardware support contracts longer than three years. Machines run until they die. They have a very high utilization of equipment (‘duty cycle’, 7 x 24 x 365). Replacing hardware makes more sense because of the lower cost and the power savings of new hardware.

How Can the Large Hadron Collider Withstand One Petabyte of Data a Second?

Why is there something rather than nothing? That's the kind of question the Large Hadron Collider in CERN is hopefully poised to answer. And what is the output of this beautiful 17-mile long, 6 billion dollar wabi-sabish proton smashing machine? Data. Great heaping torrents of Grand Canyon sized data. 15 million gigabytes every year. That's 1000 times the information printed in books every year. It's so much data 10,000 scientists will use a grid of 80,000+ computers, in 300 computer centers , in 50 different countries just to help make sense of it all.

How will all this data be collected, transported, stored, and analyzed? It turns out, using what amounts to sort of Internet of Particles instead of an Internet of Things.

Click to read more ...


Google's Colossus Makes Search Real-time by Dumping MapReduce

As the Kings of scaling, when Google changes its search infrastructure over to do something completely different, it's news. In Google search index splits with MapReduce, an exclusive interview by Cade Metz with Eisar Lipkovitz, a senior director of engineering at Google, we learn a bit more of the secret scaling sauce behind Google Instant, Google's new faster, real-time search system.

The challenge for Google has been how to support a real-time world when the core of their search technology, the famous MapReduce, is batch oriented. Simple, they got rid of MapReduce. At least they got rid of MapReduce as the backbone for calculating search indexes. MapReduce still excels as a general query mechanism against masses of data, but real-time search requires a very specialized tool, and Google built one. Internally the successor to Google's famed Google File System, was code named Colossus.

Details are slowly coming out about their new goals and approach:

Click to read more ...


How did Google Instant become Faster with 5-7X More Results Pages?

We don't have a lot of details on how Google pulled off their technically very impressive Google Instant release, but in Google Instant behind the scenes, they did share some interesting facts:

  • Google was serving more than a billion searches per day.
  • With Google Instant they served 5-7X more results pages than previously.
  • Typical search results were returned in less than a quarter of second.
  • A team of 50+ worked on the project for an extended period of time.

Although Google is associated with muscular data centers, they just didn't throw more server capacity at the problem, they worked smarter too. What were their general strategies?

Click to read more ...


6 Scalability Lessons

Jesper Söderlund not only put together a few interesting scalability patterns, he also came up with a few interesting scalability lessons:

  • Lesson #1. Put Smarty compile and template caches on an active-active DRBD cluster with high load and your servers will DIE!
  • Lesson #2. Don't use out-of-the-box configurations.
  • Lesson #3. Single points of contention will eventually become a bottleneck.
  • Lesson #4. Plan in advance. 
  • Lesson #5. Offload your databases as much as possible.
  • Lesson #6. File systems matter and can run out of space / inodes.

For more details and explanations see the original post.


4 General Core Scalability Patterns

Jesper Söderlund put together an excellent list of four general scalability patterns and four subpatterns in his post Scalability patterns and an interesting story:

  • Load distribution - Spread the system load across multiple processing units
    • Load balancing / load sharing - Spreading the load across many components with equal properties for handling the request
    • Partitioning - Spreading the load across many components by routing an individual request to a component that owns that data specific
      • Vertical partitioning - Spreading the load across the functional boundaries of a problem space, separate functions being handled by different processing units
      • Horizontal partitioning - Spreading a single type of data element across many instances, according to some partitioning key, e.g. hashing the player id and doing a modulus operation, etc. Quite often referred to as sharding.
  • Queuing and batch - Achieve efficiencies of scale by processing batches of data, usually because the overhead of an operation is amortized across multiple request
  • Relaxing of data constraints - Many different techniques and trade-offs with regards to the immediacy of processing / storing / access to data fall in this strategy
  • Parallelization - Work on the same task in parallel on multiple processing units

For more details and explanations see the original post.


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Hilarious Video: Relational Database vs NoSQL Fanbois

This is so funny I laughed until I cried! Definitely NSFW. OMG it's hilarious, but it's also not a bad overview of the issues. Especially loved: You read the latest post on and think you are a f*cking Google and architect and parrot slogans like Web Scale and Sharding but you have no idea what the f*ck you are talking about. There are so many more gems like that.

Thanks to Alex Popescu for posting this on MongoDB is Web Scale. Whoever made this deserves a Webby.


Hot Scalability Links For Sep 3, 2010

 With summer almost gone, it's time to fall into some good links...

  • Hibari - distributed, fault tolerant, highly available key-value store written in Erlang. In this video Scott Lystig Fritchie gives a very good overview of the newest key-value store. 
  • Tweets of Gold
    • lenidot: with 12 staff, @tumblr serves 1.5billion pageviews/month and 25,000 signups/day. Now that's scalability!
    • jmtan24: Funny that whenever a high scalability article comes out, it always mention the shared nothing approach
    • mfeathers: When life gives you lemons, you can have decades-long conquest to convert lemons to oranges, or you can make lemonade.
    • OyvindIsene: Met an old man with mustache today, he had no opinion on #noSQL. Note to myself: Don't grow a mustache, now or later. 
    • vlad003: Isn't it interesting how P2P distributes data while Cloud Computing centralizes it? And they're both said to be the future.
  • You may be interested in a new DevOps Meetup organized by Dave Nielson, so you know it will be good.

Click to read more ...