We want to make sure the larger size HTTP cache we're planning to ship with FF4 (bug 193911 and bug 559942) performs sanely, and so far have little testing. Here are some things to check--others feel free to add items. - Look into performance degradation that chrome reports at larger cache sizes (not sure of best way to do this), and cap our max cache size if needed. - Make sure we don't try to store more files in cache directory than minimum max of any of our supported OSes (besides correctness issue of going over max, there may also be a perf issue as we approach the limit). I know squid for instance uses multiple directories, presumably for a reason. I'll email a couple of developers there to ask about this. - Make sure clearing large cache (and also recreating cache when browser restarts after crash) does not freeze browser for appreciable length of time.