Before you scream at your screen, I am aware this setup isn't ideal, to say the least, my Self-hosting has been composed of a laptop with a usb carry with a 2.5 1tb hard drive. I recent made up my mind about getting a couple 4 tb server hdd (heard barracuda are relatively silent) to run software raid 1, since I can't find a budget double bay carry (that I can purchase locally) I've decided I'll get a couple 3.5 inch usb cases and get a splitter to run the power from just just one brick.
My question is regarding resiliency, I get occasional blackouts and low tension every now and then, a few times a year but it can be a few times in a day. I've never had hardware dying because of it and I don't have a UPS, but I worry I could be risking data corruption or something swapping to this setup because of the extra power those drives will need being fed from the wall instead of the laptop (the laptop feeds the current drive over usb alone and it has a battery) which could be abruptly cut off every now and then. Right now, the worst this has caused has been having to reboot the system because it got unmounted but never had a loss of data from this.
Am I worrying for nothing? Would it be just the same? Should I just put this off until (if) I can afford the drives plus a ups? So far I've had my server for basically free, but I'm running out of space for family photos and I kinda have to upgrade.
Edit: Thanks a lot for all the thoughtful responses! What I've learnt from them so far:
- ZFS (what's used for software RAID) takes some extra memory and might not be the best idea for a memory constrained system.
- In this case of mirrored drives, it's better to schedule backups than to try a flimsy raid array usb abomination, didn't even think of that as an option
- Sudden power loss is likely to corrupt files
- Following the previous item, a UPS is more important than I thought, my laptop's battery probably saved me from more corruption than I was aware of. I might have to prioritize that over the expansion.
Learned a lot so far, thank you all so much!
You're not worrying for nothing. Losing wall power will shut down the drives and as usb-cradle is generally slower than "proper" drive bus it's more likely that some write operation is going on when power is lost and that'll potentially cause data corruption. Obviously not every power outage will cause issues, but I'd say it's a higher risk with USB-drives than with drives on a SATA/m.2 bus.
But no matter what your setup is, raid is not a backup. All kinds of things can happen which cause loss of data and you should plan accordingly. If all you have is two drives on usb-cradles I might choose to use one of them as a offline backup disk and one for 'live' data so that it's more likely that at least one of the drives is functional even after power issues or whatever, but that approach has it's own problems too.