“Q1: What is the $ORACLE_HOME/dbs/hc_.dat file?
A1: The $ORACLE_HOME/dbs/hc_.dat is created for the instance health check monitoring. It contains information used to monitor the instance health and to determine why it went down if the instance isn’t up. The file will be recreated at every instance startup.
Q2: What happens if the $ORACLE_HOME/dbs/hc_.dat file is deleted?
A2: Per Bug 4645405 UNABLE TO START DB – ORA-7445 [KSIHSMRINI()+152] [SIGBUS],
if you replace the file with an empty “dummy” copy, you will get an ORA-7445 error. Therefore, if the file gets deleted on the fly while the database is up, or if the file is replaced with a 0 byte file, simply delete the file and restart the database. The file will be correctly recreated at the next database startup.”
Filed under: Oracle DBA