You can also save the recordings via FTP to any NAS that supports FTP or FTP servers on the Internet. See the operating instructions on page 32.
The space requirement is small for the max resolution 640 x 480 of this camera / depending on the resolution and image quality setting.

Hi, you can definitely use this camera with a Synology NAS. it works very well. Except that there are problems with the sound. But the video and the quality is good.
I have it set up to record only a few seconds during (before and after) a movement. And it's like 3-5MB per 20 seconds for me.