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Wednesday, May 5, 2021

OEM 12c/13c Database Target Discovered and Named with host name as suffix

 When EM discovers database targets, it generates default target name for the database in one of following formats,

  db_unique_name.db_domain   if both parameters db_unique_name and db_domain are set
  db_unique_name             if parameter db_unique_name is set, but db_domain is not set
  db_name.db_domain          if parameter db_unique_name is not set, but db_domain is set
  db_name                    if neither db_unique_name nor db_domain is set

EM discovery script retrieves these parameters' values from parameter file (pfile or spfile) of the database, not from running instance. If the discovery process has issue to locate or process parameter file, EM will name database target in format,

  <sid>_<hostname>
  
Therefore, when you find the new discovered database target is named in this format, it means EM agent discovery script has issue with parameter file. The details can be found from agent trace file "<AGENT_INST_HOME>/sysman/log/emagent_perl.trc". Most popular error messages look like

  ERROR:  initParameterFileUtl::convertSPFileToPFile: Failed to convert spfile
  
or

  ERROR:  initParameterFileUtl::getParameterFile: Cannot find any init parameter file for instance <instancename> in oracle home  <oracle_home>

For example, when Oracle Restart (standalone Grid Infrastructure) is installed and ASM storage is configured on server host1.dbaplus.ca, DBCA creates a database orcl (sid & db_name) in ASM diskgroup, the spfile will also be saved in ASM diskgroup and no parameter file (pfile/spfile) will be created under directory <ORACLE_HOME>/dbs. The database will be discovered by EM with default name orcl_host1.dbaplus.ca and you will see errors in agent trace file "emagent_perl.trc",

oracledb.pl: 2021-05-04 04:03:08,923: INFO:  DB_LISTENER_DISCOVERY:  processing sid="orcl"
oracledb.pl: 2021-05-04 04:03:08,926: ERROR:  initParameterFileUtl::getParameterFile: Cannot find any init parameter file for instance orcl in oracle home /u01/app/oracle/product/19.9.0/dbhome_1/dbs
oracledb.pl: 2021-05-04 04:03:08,930: ERROR:  initParameterFileUtl::getParameterFile: Cannot find any init parameter file for instance orcl in oracle home /u01/app/oracle/product/19.9.0/dbhome_1/dbs
oracledb.pl: 2021-05-04 04:03:09,065: ERROR:  initParameterFileUtl::getParameterFile: Cannot find any init parameter file for instance orcl in oracle home /u01/app/oracle/product/19.9.0/dbhome_1/dbs
oracledb.pl: 2021-05-04 04:03:09,069: ERROR:  initParameterFileUtl::getParameterFile: Cannot find any init parameter file for instance orcl in oracle home /u01/app/oracle/product/19.9.0/dbhome_1/dbs

The reason is that discovery script cannot find parameter file from <ORACLE_HOME>/dbs. To fix this problem, create a pfile 'initorcl.ora' under <ORACLE_HOME>/dbs with following content,

   spfile='<full path of spfile saved in diskgroup>'

Note: DO NOT leave any SPACE character at the beginning of the line (before word "spfile"). If you did, you will not see any errors in the trace file, but the target name will be <sid>_<hostname>.

Sample init file

$ srvctl config database -db orcl | grep spfile
Spfile: +DATA/orcl/PARAMETERFILE/spfile.919.1071658047
$
$ echo "spfile='+DATA/orcl/PARAMETERFILE/spfile.919.1071658047'" > $ORACLE_HOME/dbs/initorcl.ora
$
$ cat $ORACLE_HOME/dbs/initorcl.ora
spfile='+DATA/orcl/PARAMETERFILE/spfile.919.1071658047'

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