Answer
IFS Data Archiving is the built-in mechanism designed for exactly this kind of situation, rather than manually copying data into a Custom Logical Unit — it's purpose-built to move historical records out of the actively-queried tables while keeping them retrievable for archival and analysis purposes, and it understands the actual relationships and dependencies of standard records (like Customer Order Lines) in a way a hand-built custom-LU copy wouldn't. Reviewing the Data Archiving documentation for the general archiving process (and whether Customer Order Lines specifically has archiving support) is the better starting point than building a custom migration of this data yourself.