After couple failed hard disks in my old NVR, I’ve come to realize heat is the biggest enemy of hard disks. The NVR had to provide power to the POE cameras, ran video transcoding, and constantly writing to the disk. It generated a lot of heat. The disks were probably warped due to the heat and the disk heads crashed onto the surface, causing data loss.<p>For my new NVR, the POE power supply is separated out to a powered switch, the newer CPU can do hardware video encoding, and I used SSD for first stage writing and hard disks as secondary backup. The heat has gone way down. So far things have run well. I know constant rewriting on SSD is bad, but the MTBF of SSD indicates it will be a number of years before failing. It’s an acceptable risk.