I used to setup a ramdisk as a flat file for / and /usr, and have it load unionfs style over the main filesystem after /sbin/init finished. This was around 2005

I used to setup a ramdisk as a flat file for / and /usr, and have it load unionfs style over the main filesystem after /sbin/init finished. This was around 2005. The system flew, and the only super large applications I was using installed to /opt anyway, which was on a spinning disk (I think Eclipse was the only one).