D-Link DCS-3511 User Manual page 63

Configuration
Enable cyclic recording: If you select this item, when the maximum capacity is reached, the oldest file will be overwritten by the latest one. The
reserved amount is reserved for cyclic recording to prevent malfunction. This value must be larger than 15 Mbytes.
If you want to enable recording notification, please click Application to set up. Please refer to Trigger > Recording notify for detailed information.
When completed, select Enable this recording. Click Save to enable the setting and click Close to exit this page. When the system begins
recording, it will send the recorded files to the Network Storage.
The new recording name will appear in the drop-down list on the recording page.
To remove a recording setting from the list, select a recording name from the drop-down list and click Delete.
D-Link DCS-3511/DCS-3530 User Manual 63