Is there any procedure for data integrity check and/or repair of inconsistency, if it appears?
Nuxeo EP has been designed to completely rely on RDBMS data integrity (that can be considered trustable nowadays). One can use RDBMS tools to check data integrity/consistency and data failure if any. If the data model is corrupted, Nuxeo EP warns about it when the repository starts. Indexes (from Nuxeo Search) can be verified and easily be rebuilt by reindexing the content if any problem occurs.