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?
IMO, a Pi running off a MicroSD card is by far the highest failure risk you have in this configuration. Most modern spinning disks are more than capable of being a backup workhorse, while MicroSD cards feel like a crapshoot.
For backups, I’m a fan of pretty much anything new from Seagate or WD (failure rates are minimally different), though you can also check Backblaze’s quarterly reports if you want to get specific.
My other go-to is just used enterprise HDDs (usually SAS for my configuration, but SATA is there too) since such drives often come with very low write life used, and generally incorporate features that make for an extremely high MTBF. Though it’s obviously hit or miss if you get a drive that was barely used or a drive that was beaten to death. Good eBay sellers usually are pretty good about these things though.
In either case, you’ll need an enclosure (obviously if buying new, you can just buy one with the enclosure).
Yeaaah I know but it's all I've got right now. I plan on keeping a backup image of the microSD image in case it breaks I can just swap it out.
Thanks for the advice! Do you think SyncThing would be the most straightforward way of doing it? I'm running CasaOS for most apps but have HA in a virtual machine.
Try one of those endurance micro SD cards, since you dont need a lot of storage for OS they should be pretty cheap like 32gb is like $12.
Great to know about, thanks. SanDisk has 64gb for $10 on Amazon (32gb for $12 lol)
May be worth doing backups with something like rsnapshot. That way you'll have history in the event of any data corruption.
+1, all of my SBCs that do important things have the OS installed on an SSD plugged into a USB3 enclosure and (if needed) only the bootloader and /boot on an SD card. That cuts wear on the SD down to almost nothing. Pick up a good condition msata or m.2 2230/2242 drive on eBay and stick it in an enclosure and watch SMART stats and you shouldn't have any unexpected failures.