Hard Disk – How to make the hard drive a lazy copy of the SSD?

I want to build a PC with a 500GB SSD and a 500GB hard drive, and of course other drives, but they do not matter in this matter. How to make this hard drive a silent copy of the SSD? I mean that all data on SSD should be "reflected" on the hard drive in "lazy" mode. I've read articles on RAID, but if I understood correctly, this is not exactly what I need because the speed of writing SSDs in RAID will be limited by that of the hard drive.