March 2005 Archives

Below are a few R functions I use to evaluate and tune our Squid caches, which we use in accelerator mode. The functions work by taking a real stream of requests from either an application or squid log. From there the arrival rate can be determined at every second. Or a filter can be applied and the cache hit ratio or arrival rate re-determined. Or better yet, the series can be filtered a number of times with different filter values to determine the best value for a given filter.

Our new offices are rife with small issues like the A/C working randomly or inconsistently. In response, many people believe it is to their benefit to set the thermostat (t-stat) to the lowest setting since there is no obvious means to tell if the A/C just isn't working.