SMART (Self-Monitoring, Analysis, and Reporting Technology) is a
feature of hard drives that allows them to detect symptoms of disk failure and
relay an appropriate warning.
The smartd service can be disabled with the following command:
$ sudo systemctl mask --now smartd.service
SMART can help ensure availability of systems by notifying system operators of failing hardware. Nevertheless, if it is not needed or the system's drives are not SMART-capable (such as solid state drives), this service can be disabled.