Morten asked:

..I can't really use any external storages, as the reason for bringing these objects into the ZODB was to structure them and make then indexable by ZCatalog

This sounds like the sort of thing ExtFile was made for. Your metadata still lives in the ZODB, but points to the files on the file system. Also, LocalFS can be used to allow a Zopeish way of accessing the files for updates, uploads, etc. http://www.zope.org/Members/MacGregor/ExtFile http://www.zope.org/Members/jfarr/Products/LocalFS Good luck! Jerry S.