Oct 26 2010 - Squeezing out more performance

Adding a web server at Auckland will help cope with the demand for the website straight after the bigger Darfield aftershocks. But within a week of its deployment, we hit the stops again after the magnitude 5.0 earthquake on Tuesday 19 October.

The quake occurred at 11:32 am. Prior to the quake, the website was sitting at about 110 requests/second. After the quake we rose to more than 9,500 requests/second in 5 minutes, eventually topping out (at a new high) of 11,622 requests/second, 13 minutes after the shake. So the extra capacity of the new server was good for slightly less than a week!

We have now installed all the spare servers we have at FX Network's data centres, so we've looked at getting more out of them. Some of the things we've done include:

Optimizing the content

During the aftershocks from the Darfield earthquake the Recent Quakes page has become the most popular page as people want to view the aftershocks in a time-ordered list. The optimization reduces the number of requests to the server that are needed to load the page - this makes the page load faster in your browser as well reducing the load on the server. We have applied more of the optimization techniques outlined last year as well as changing the way we make and name the earthquake location key map. Now depending on the way the earthquakes are clustering together across the country, the number or requests to load the Recent Quakes page could be reduced by up to 30; currently it is at 28 requests, down from 46 before the change.

Security system tuning

Resources were reallocated to overcome a bottleneck in the security layer that only became apparent under heavy load.

Domain sharding

Domain sharding is a trick to let a browser open parallel connections to the content and make the page load faster. We have brought forward our plans and have implemented this for the GeoNet website.

Our next steps

We plan to install a further web server at Christchurch, and upgrade the web servers in Wellington and California sooner than planned, as they are scheduled for replacement in the next few months anyway.

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