Solution : https://service.sap.com/sap/support/notes/210385 (SAP Service marketplace login required)
Key words : 
symptom error=27063 txt 'ibm aix risc system/6000 error, aio maxreqs = 12288 und /usr/samples/kernel/vmtune -, run /usr/samples/kernel/vmtune -, additional key words aix 4, numfsbufs von 93 auf 200 erhöht, aio maxreqs parameter, resource terporarily unavailable, oracle database shuts, prerequisites solution increase, successful problem solutionin
Related Notes : 
       
| 793113 | FAQ: Oracle I/O configuration | 
| 546006 | Problems with Oracle due to operating system errors | 
| 328785 | ORA-00376: File cannot be read at this time |