SAP Note 22026 - Duplicate database background processes/ORA7429

Symptom:

The symptom can be expressed in two ways.
- Duplicate database background processes (example):
Check: ps -ef | grep smon
c11adm 4507 1 0 Jun 4 ? 4:49 ora_smon_C11
orac11 4711 1 0 Jun 4 ? 4:49 ora_smon_C11
oras11 28837 26255 4 13:50:43 ttypb 0:00 grep smon
- ORA7429 smsgsg: shmget() failed to get segment
when connecting to the database

Cause and prerequisites

Linked ORACLE_HOME (example)
cd /oracle
ls -al
lrwxrwxrwx 1 root other 12 Jun 07 15:05 C11 -> /usr/ora/C11

Solution
Dissolve the link (most effective solution)
- or -
ORACLE_HOME must be configured the same, system-wide, in all environments.