The db2acd process in DB2 Version 9.x will still run when database configuration parameters HEALTH_MON and AUTO_* are set to OFF
DB2® Version 9.x process db2acd is a single process that runs in parallel for both health monitor and automatic maintenance functions.
When HEALTH_MON=OFF and AUTO_* database configuration parameters are set to OFF, db2acd will still wakeup approximately every 2 hours to check for active database automatic maintenance.
Setting registry variable DB2_FMP_COMM_HEAPSZ to 0 will prevent db2acd from starting. This means no set is created, and as a result, no fenced routines can be invoked. It also means that the health monitor and the automatic database maintenance functionality (such as automatic backups, statistics collection, and REORG) will be disabled since this functionality relies on the fenced routine infrastructure.
If DB2_FMP_COMM_HEAPSZ is not (cannot be) set to 0, we cannot disable db2acd completely due to its original design. The db2 system controller (db2sysc process) will restart db2acd process if it is killed and this checking is done every 15 minutes.
For more detail on setting DB2 registry variable and DB2 Database Manager Configuration, please see section "Related Information".