When you are migrating any of the database areas to a larger size:
AR-AREA ,RD-AREA, OV-AREA, SG-AREA, RD-STAT-AREA, DQ-AREA, or OQ-AREA,
It is critical that you backup your Dispatch LOAD LIBRARY as well as the DICTDB, DLODDB, and DMSGDB database files.
You also need a backup the area/database file that you will be migrating to a larger size.
The reason for this is that there are size modules in the Dispatch loadlib that know the sizes of all of your DB areas. Your "dictionary" database files (DICTDB,DLODDB,DMSGDB) also know the sizes of your DB areas. Both the loadlib and dictionary are updated as part of the migration process.
If any sort of problem occurs during the migration, all of these areas and the loadlib need to be restored.
The second critical step is after the migration and DSEXDBEX jobs are run, you should backup all the area's and the loadlib again in order to capture everything at the new size.