NeverBlock Saves The Day


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It started with too many processes

A great proof of how valuable NeverBlock is happend just a little while ago. is one of the oldest forums in the middle east. Lately, I helped rebuild the whole thing and move it to Ruby on Rails while I was at eSpace, my previous employer.

Many web users rely on sites like for following commentary on breaking news, thus during such events the daily page views can jump from a couple hundred thousands to millions. Add to that the fact that there are some (unavoidable) slow database operations that must be done online for the administrators.

Initially we had different web server instances for the normal users and administrators to avoid stalling Rails processes on long running queries. All in all, since we had a capable back end, we coupled it with a formidable number of Rails processes as front end servers. This was the only way back then to exploit our back end's conncurency. Needless to say, this army of front end processes consumed lots and lots of memory.

Enter NeverBlock

After the initial production testing in, we thought of the gains we can get from using it with Alsaha, so we planned for the move and were able to drastically reduce the Rails instances count. We only use 4 now and this is for utilizing the CPU cores rather than concurrency. Those 4 processes serve all the user and administrative content. Thanks to NeverBlock, no one has to wait for the other.

The Real Test

There was a very important news item lately that resulted in a traffic spike in the order of millions of page views in a few hours. Thankfully, the NeverBlock setup easily accomodated that without noticeable degradation (actually there was some degradation attributed to a bug in the logging logic, that was quickly discovered and fixed). The small 4 instances kept up with the load even though some slow operations were running on them while they were serving loads of quick ones to lots of users.


I am grateful to have written code that turned out to be useful to others. I hope this would be a pattern.

My RubyKaigi 2009 Presentations


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Better late than never :)

I totally forgot to link to my RubyKaigi 2009 presentations, so without further ado, here they are:

NeverBlock, the video:

NeverBlock, the slides:

Arabesque, the slides