I come from the SQL server world so I don't know enough about DB2 to be dangerous. I understand that to insert, update, delete records in DB2 from external sources such as SQL server, the underlying file in DB2 needs to be journaled. We even have an application that uses JDBC to connect to DB2 and needs the file it inserts to be journaled (it is an instruction in the installation documentation)

My question is, why do DB2 DBA's not want any journals? What is the case for why this is said?

I want to know the technical details of this rule of thumb. Thank you