Note 454927.1 Using and Disabling the Automatic Diagnostic Repository
(ADR) with Oracle Net for 11g
Sqlnet.ora file on either client or server:
DIAG_ADR_ENABLED=OFF
Listener.ora file:
DIAG_ADR_ENABLED_<listener_name>=OFF
CMAN.ORA:
DIAG_ADR_ENABLED=OFF
ADR_BASE=c:\your_directory