This is a guest post by Bob Reselman.
Any test you run will only be as valuable as the breadth and accuracy of the test data you collect. However, collecting test data can be hard, if not nearly impossible, when the digital infrastructure is spread across the planet. The trick is to implement distributed tracing.
This is a companion discussion topic for the original entry at http://feedproxy.google.com/~r/gurock/~3/2bMegBcKumg/