A new breed of tools have started appearing on our radar supporting the very idea of automated visual regression.

CloudFront is a content delivery service offered by Amazon web services(AWS). CloudFront serves static contents (images, audio, video etc) using a global network of more than 28+ edge locations. Using these edge locations, CloudFront accelerates delivery of content by serving the cached copies of the content objects from a nearest edge location. Service is highly reliable and designed to be used with Amazon S3 or any other custom origin server.

Celery is an asynchronous distributed task queue. RabbitMQ is a message broker which implements the Advanced Message Queuing Protocol (AMQP). Before we describe relationship between RabbitMQ and Celery, a quick overview of AMQP will be helpful ^{1 2} . Amqp Key Terms Message Or Task A message or task consists of attributes (headers) and payload (body). Some attributes are used by broker but most are used by consumers.

Proud to say that this blog is now written in Markdown using iA Writer, generated by Jekyll static blog generator and hosted by Amazon S3 which costs me less than 1$ a month. Over the years I moved my blog from Blogger to Wordpress to Self- hosted Wordpress to Scriptogram and finally to Jekyll/Amazon S3. In case you want to migrate to Jekyll generated static blog content hosted by Amazon S3, you can find more technical details here.

Way before Google-scale or Facebook-scale existed, there was Visa-scale. This COMPUTERWORLD article from 2001 provides some insights about early Visa payment processing infrastructure. Scalability, Reliability and Security Visa payment processing infrastructure uses multiple layers of redundancy and backups (3 layers or more). Visa uses a global network of payment processing data centers.

First of all Happy New Year to you all. Honestly speaking this post was due in first week of this month but it’s not too late for new year’s resolution. As matter of fact I desperately wanted to write this post - to share my excitement for year 2013 and also humbling experience in 2012. 2012 2012 was phenomenal, both personally and professionally especially considering a rather depressing 2011.

Recently I moved my blog from Scriptogram to static site generated by Jekyll and hosted on Amazon S3. I am a big fan of Vagrant and I really like the way it keeps clean separation between various development environments without affecting host operating system. This post will explain how you can set-up a Vagrant instance for Jekyll based blogging supported by S3 hosting.

For those who never heard about the Vagrant, it is a very handy way to manage, create and destroy headless virtual machine (VM) environments.

My notes and thoughts on Hadoop Ecosystem from book Hadoop Operations ¹ . One of the major key take aways is emergence of the Hadoop cluster deployment and management tools such as hstack and Apache AMBARI. In our own setup we managed to deploy and scale the Hadoop clusters on AWS with few boto scripts and set of puppet recipies.

Notes plus thoughts from my recent read Cassandra: The Definitive Guide. Common ways to solve scalability bottleneck with relational databases, Throw More/better Hardware (memory And Cpu) Vertical scaling Faster disks (SSD vs RAID) Move To A Database Cluster With master-slave configuration: Master is now single point of failure. Update slave as master during failure. Separate read from writes - dedicated slaves for reads.

Polyglot persistence which takes a hybrid approach to persistence is getting a lot of traction these days. Currently I am reading NoSQL Distilled: A Brief Guide to the Emerging World of Polyglot Persistence by Pramod J. Sadalage and Martin Fowler. Basic idea behind polyglot persistence is to use specialized databases (both NoSQL and Relational) for different purposes within the same web application.