Every day at 11:44 and 16:16 we would receive errors from ASM on server03 like the following:
ORA-15173: entry 'dbprd3' does not exist in directory '/'
Besides the error not giving a lot of detail, we found it weird that database "dbprd3" is involved as it hasn't existed on this server in a long time.
Since the problem would happen at specific times daily, it seemed likely that the cause of this error was related to a scheduled job of some kind. But, the "oracle" account is locked down on this server which means "oracle" can't use cron. No OEM Jobs are listed as having run during the times the errors are generated plus the target "dbprd3" doesn't exist in OEM.
After performing a few searches on server03 for files with "dbprd3" in the name, tracefiles were found under $ORACLE_HOME/rdbms/log, named dbprd3_ora_[PID], listing only 1 error line:
KGFCHECK kgfnStmtExecute01c: ret == OCI_SUCCESS: FAILED at kgfn.c:1563
Going back to OEM, it was found that "dbprd3" was still listed as a discovered yet unpromoted target on server03. Deleting this target (since it doesn't exist) and running an immediate discovery process generated the errors in question. The easy fix at this point was to disable auto-discovery and in fact it should be disabled for all servers, since we never need it unless something new is added.
Next came the question as to why the discovery process would generate the errors. Since the discovery process is handled through the management agent, emagent_perl.trc under $AGENT_INSTANCE_HOME/sysman/log was checked for details, which revealed the following:
oracledb.pl: Wed Nov 7 16:16:55 2018: ERROR: initParameterFileUtl::convertSPFileToPFile: Failed to convert spfile +DATA/dbprd3/spfiledbprd3.ora to pfile using sqlplus: Inappropriate ioctl for device 0 The output of sqlplus is "CREATE PFILE='/tmp/r3VRTW7BT5' FROM SPFILE='+DATA/dbprd3/spfiledbprd3.ora' * ERROR at line 1: ORA-01565: error in identifying file '+DATA/dbprd3/spfiledbprd3.ora' ORA-17503: ksfdopn:10 Failed to open file +DATA/dbprd3/spfiledbprd3.ora ORA-15056: additional error message ORA-15173: entry 'dbprd3' does not exist in directory '/' ORA-06512: at line 4
The discovery process was finding database "dbprd3" and then trying to gather more information about it, but that failed since it was removed previously. /etc/oratab was checked, as that's one of the files the discovery process checks, and sure enough "dbprd3" was still listed. The final clue came from reviewing the details listed in emagent_perl.trc - "oracledb.pl: Wed Nov 7 16:16:55 2018: ERROR: initParameterFileUtl::convertSPFileToPFile". The discovery process runs several Perl scripts under $AGENT_BASE/plugins/oracle.sysman.db.discovery.plugin_[RELEASE]/discover, oracledb.pl being one of the main ones. This calls ./utl/initParameterFileUtl.pl, which generated the error in subroutine "convertSPFileToPFile". It seems the discovery process tries to gather additional details about databases it finds from the init.ora file. The subroutine tries to generate a text file based on the spfile and the spfile location, in our case, is determined by the init.ora file under $ORACLE_HOME/dbs. Sure enough, that file was still present for "dbprd3" and had one line:
SPFILE='+DATA/dbprd3/spfiledbprd3.ora'
When the database "dbprd3" was removed in the past, so was all its ASM files, including the spfile. By disabling auto-discovery, then removing the entry in /etc/oratab and removing the init file, the problem was eliminated for good, even if someone manually executes the discovery process later.