JNLEXTEND, Journal file extension error for file jjjj.
Run Time/MUPIP Error: Journal file jjjj failed to extend. If the environment is not configured for instance freeze, this causes journaling to be turned off for the region.
Action: Review the accompanying message(s) and take appropriate action. If the environment is not configured for instance freeze, perfrom a MUPIP BACKUP, that turns journaling on again, to reestablish durability.