Erlang Factory 2014 – That’s ‘Billion’ with a ‘B’: Scaling to the Next Level at WhatsApp


Install Perl modules without root rights on Linux

“If you have root rights there might be other, easier ways to install Perl modules than the following.

After an initial configuration, many Perl modules from CPAN can be easily installed, but there are quite a few that required some additional tools. In this article I’ll assume that either you already have those installed, or that at least those you can install as root.

If you don’t have those prerequisites then you will need to build the modules on another, similar machine where you do have root rights and then transfer the whole directory tree. That’s another story that will be covered in a separate article. In that situation you’d be probably better off downloading and using DWIM Perl…”

The tech behind our time series graphs – 2bn docs per day, 30TB per month

“Server Density processes over 30TB/month of incoming data points from the servers and web checks we monitor for our customers, ranging from simple Linux system load average to website response times from 18 different countries. All of this data goes into MongoDB in real time and is pulled out when customers need to view graphs, update dashboards and generate reports…”

Redis as the primary data store? WTF?!

“Redis is a key-value in memory data store typically used for caches and other such mechanisms to speed up web applications. We however store all our data in Redis as our primary database.

The web is abound with warnings and cautionary tales about going this route. There are horror stories about lost data, hitting memory limits, or people unable to effectively manage the data within Redis, so you might be wondering “What on earth were you thinking?!” So here is our story, why we decided to use Redis anyway, and how we overcame those issues…”