From Oracle FAQ
SMON (System MONitor) is an Oracle background process created when you start a database instance. The SMON process performs instance recovery, cleans up after dirty shutdowns and coalesces adjacent free extents into larger free extents.
SMON wakes up every 5 minutes to perform housekeeping activities. SMON must always be running for an instance. If not, the instance will terminate.
The following Unix/Linux command is used to check if the SMON process is running:
$ ps -ef | grep smon oracle 31144 1 0 11:10 ? 00:00:00 ora_smon_orcl
|Glossary of Terms|