Unloading the existing database

Unload the existing database by using the IMS HD Reorganization Unload utility (DFSURGU0).

Specify the MIGRATE=YES control statement. The MIGRATE=YES control statement identifies this unload as being part of the HALDB conversion process. The IMS HD Reorganization Unload utility must use the DBD that defines the non-HALDB database.

Recommendations:

If you currently use OSAM database data sets, use OSAM sequential buffering when unloading the database. OSAM sequential buffering typically improves the performance of the unload.
If the database that you are migrating is large and you are using the MIGRATE control statement, the DFSURGU0 utility can unload records in ranges of keys. Multiple key ranges can be unloaded in parallel jobs to improve unload performance.