How in the Tech

Relocating Firefox’s cache directory off your SSD

By Adam Myers ⋅ May 20, 2010 ⋅ Tags: Firefox

Yesterday I detailed the process on relocating Google Chrome’s user profile directory and today I’m going to describe the steps necessary to do the same in Firefox. First, let’s revisit why this may be something you wish to do.

Solid state drives or SSD are gaining popularity by leaps and bounds. The performance improvements over a traditional hard drive are astounding and as the price continues to fall, the upgrade option becomes available to a wider range of budgets. While SSD is lightening quick there still remains a few draw backs. First, the size available is limited, at least at sanely priced units – this limits them to mainly your operating system and application installs and not your collection of media; you’d need a second hard drive for that. In the end, that’s a small compromise for many. Secondly, SSD has the notion of limited writes. Simply, the drive can only be written to a certain amount of times before it becomes worn out. It should be stated that USB thumb drives or other types of memory cards, such as for your camera, suffer the same problem.

While limiting the writing of data to the SSD is good a computing practice, it’s not something to overly stress over. However, there are a number of customizations that you should strongly consider that are painless, and can help limit the writes – all without really affecting the overall performance.

One such tweak involves relocating your browser user and cache directory off your speedy SSD C drive onto a secondary drive. As every visit to every web page generally involves the writing of some cache information to the disk, moving this off of SSD is logical.

Like Chrome, Firefox doesn’t make this relocation process apparent in their user interface. Rather, the change is accessible by accessing about:config from the address bar.

From the Filter box search for the key browser.cache.disk.parent_directory. If the key doesn’t exist, as it didn’t in my default Firefox 3.6 install, it can be created by right-clicking and choosing New->String.

For the string value provide a path to a folder on your secondary hard drive that you wish to use; restarting Firefox to apply the change. Here I chose the folder d:\ff_cache.