My goal is to create an simple offsite backup of my CasaOS setup using a RasPi 3b+ with external USB drive at a friend’s house. Are there any recommended methods for doing this?
Also: what should I look for in an external hard drive as far as reliability goes for something that will essentially always be on? I’m not well versed in all the WD blue, red, etc. Does it matter?
Flash drives are notorious for spontaneous and ungraceful failures. At the very minimum, you want a proper Hard Drive or SSD. Generally, any reputable brand marketing a “NAS” drive is probably what you want. Nothing spectacularly fast, but designed for a lot of power on hours.