Solution : https://service.sap.com/sap/support/notes/744055 (SAP Service marketplace login required)
Key words : 
system managed access path protection, 'r3<sid>data qsqjrn     file     ', /pubs/html/as400/infocenter, sap<sid>jrn reason, sap<sid>db/qdftjrn, data area called qdftjrn, r3<sid>jrn, sap<sid>db, r3<sid>data, auxiliary storage pool
Related Notes : 
       
| 1449715 | IBM i: Current recommendations for journal configuration | 
| 828354 | iSeries: Set up journal logging manually | 
| 654801 | iSeries: ASP configuration of the database for ABAP and Java | 
| 585277 | iSeries: Performing a Homogeneous System Copy | 
| 443925 | iSeries: SAP Systems on DB2/400 in comparison with MCOD |