I have written some scripts for Knoppix to realize a "drive friendly" persistence: saving changes to HDD only at shutdown (or anytime you want). While in the traditional way changes to live system are written immediately to persistence data storage file.
Now I want to do this for Debian Live, too. But there is a problem. In Knoppix there is a /ramdisk directory where all changes to live system can be found. I can easily synchronize this directory with a directory on HDD (and vice verse). But in Debian Live I cannot see any directory containing the changes to live system. I think due to the fact that Knoppix uses UNIONFS.
Does exist such a directory in Debian Live? If not, how can be saved the changes to live system into a directory?