My new server is using an external 1TB disk to store all what seems necessary. In order to keep the disk under surveillance of smartmontools without loosing the power management and spin down options of hdparm I am using the following settings:
/etc/hdparm.conf:
/dev/sda {
spindown_time = 24
}
/etc/smartd.conf:
DEVICESCAN -d removable -n standby -m root -M exec /usr/share/smartmontools/smartd-runner
-m root: send email notification to root user
-n standby: only run tests if device is not in standby mode