Finally I updated from 1.0.7 to 1.0.8, an imported the nodes table. Everything works fine and the db is running faster. During the installation I noticed these things, maybe they can be fixed in further versions:
1. nedi.conf changed in 1.0.8 but the version is commented with '# NeDi 1.0.7 configuration file' - a bit confusing :-/
2. file structure: all files (binaries, scripts and data) are stored in /var per default. Especially rrd can get very big (30 gig in my set up). I recommend to put
- binaries to /opt/nedi and
- data to /var/nedi
on different partitions/volume groups. At the moment I solved the problem with links.