Lessons learned

Migration from Plone 2.0 to 4.0

>100.000 content objects

>40GB in size

many custom products

usual migration/upgrade failed

So what did I learn:

make migration repeatable (eg: using GenericSetup upgrade steps)

migrate parts of page separatly

split migration into export and import part

monitor and time migration

don't complicate in making blueprints extra reusable