SMART(Self Monitoring Analysis and Reporting Technology) is a feature provided by HDD. It monitors possible conditions that the HDD has been exposed to, or status for HDD errors.

Your DVR can be configured to set the SMART information check schedule and condition. It can send alarm out or notification on SMART error.

If you see SMART error messages, it may be a good idea to change the HDD. Because it means your HDD could be damaged.