Varnish and Graphite

At work we have a reasonably busy Varnish cluster.  We hooked it up to Graphite to allow near real-time visualization of how busy it is.  Here’s a sample of what part of our Graphite dashboard looks like when you look over the past four months:


Effects of Windows 2008R2

The effects of upgrading a (deliberately unnamed) web application from Windows 2003 to Windows 2008R2:


Passive Indexing Wins Again

180px-Bogleheads_facebook_logoI’m a bit of a Boglehead, and the data appears to back me up.  From

In 2012, 63 percent of large-cap funds, 80 percent of mid-cap funds and 67 percent of small-cap funds underperformed [relative to their benchmark]. The only asset class to see the majority of active funds outperform was large-cap growth, with 54 percent beating their benchmarks. The worst performance came in mid-cap growth funds where 87 percent failed to outperform.

As we would expect, the performance tends to worsen when we look at longer periods. This is because the typically higher expense ratios of active funds become a greater burden over time. For the past three-year and five-year periods, 86 percent and 75 percent of large-cap funds underperformed, 80 percent and 90 percent of mid-cap funds underperformed, and 67 percent and 83 percent of small-cap funds underperformed, respectively. And there were no asset classes where a majority of active managers outperformed.

Scaling Varnish

As seen on

I read one web testimony of a person who used Varnish to scale a site up to almost 200 million page views a month.

I’d like to find someone who has that level of expertise.

At work we have a Varnish cluster which, during the month of March, served over 17 billion requests for an average of 6,400 requests/second.

This cluster contains two physical machines with 24 cores and 192GB of RAM apiece.  These machines have tons of spare capacity; their load average peaked at approximately 4.  We’ve even considered virtualizing the cluster.

Varnish is a pretty amazing piece of software.

Technology Koans

I find these amusing and thought-provoking:

Unix File Extension

This useful little snippet can be used to find the unique list of extensions for all files in a directory and all its subdirectories.  I can never remember the precise awk incantation for this:

$ find . -type f | awk -F. '{print $NF}' | tr '[:upper:]' '[:lower:]' | sort -u
%d bloggers like this: