Hello this is my first contribution in this group is quite simple but had complicated for several hours to a colleague basis. after the end of the upgrade from 10G to 11G oracle was impossible to start the SAP system. The first review to perform and give light on the error. the execute R3trans–d showed the following:
The error ORA-27101 indicating that the database was down. but it really was up
After reviewing the system I found the cause of the problem. the listener still maintained the ancient oracle 10G engine settings (ORACLE_HOME):
the problem was solved change configuration listener and restart:
Then R3trans -d are OK and sap start without problems.