I have also been moving things to opt and symlinking them. I have found that it is best to create a directory in opt and mirror the root off that with the things you plan on moving. This in itself documents what was moved to where. I use /opt/reclaim to do this:

Thing I have symlinked to /opt to save up on root space without issue:



/usr/share/hildon-welcome/media -> /opt/reclaim/usr/share/hildon-welcome/media
1.4MB

/var/lib/apt -> /opt/reclaim/var/lib/apt - 14MB if you have extras-devel enabled
/var/lib/dpkg -> /opt/reclaim/var/lib/dpkg - 3MB

/usr/share/sounds -> /opt/reclaim/usr/share/sounds - 3MB

/usr/share/fonts/chinese -> /opt/reclaim/usr/share/fonts/chinese - 2MB
/usr/share/fonts/arabic -> /opt/reclaim/usr/share/fonts/arabic - 1MB