If more than one Oracle instance is monitored on the same host, mutiple VMSTAT and IOSTAT commands are created causing a high CPU utilisation.
Disable the OS collections for all of the instances except for one.
Disable the "File System IO" collection to stop the IOSTAT command.
The VMSTAT command is run by a collection that combines OS and JDBC collection information so this is slightly more problematic to disable.
Revoke the permission for the OS user to execute the IOSTAT/VMSTAT commands.
Doing this would cause the Agent logs to get errors printed into them; however, it would also stop these commands from executing without disabling the entire OS collection.