This is offtopic, but a topic dear to any true computer geek's heart, so:
Quote:
Originally Posted by Quoth
Not all spinning disc HDD are suitable. Avoid too high density, helium or shingled drives.
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I semi-agree about helium (iff there was a danger of it leaking out, which I was worried about but which seems to just not happen at any timescale you'd care about
: I don't really care if my backups are unreadable in 200 years). High density, well, the higher density a drive is the *harder* it is to demagnetize. So I'd ignore that (and use par2 for redundancy anyway). I certainly wouldn't avoid shingled drives if using a backup program that mostly does great big linear writes (as most do). Shingled drives seem absolutely ideal for this use case.
But more generally I'd avoid brand new drive models (which usually means avoiding the latest ultra-high-capacity stuff anyway), and also would avoid complex filesystems: only use filesystems (and features of those filesystems) that have been around for ages, since they are less likely to fall prey to fs-eating bugs. (I only just moved from ext2 to ext4 on my backups so I could start using metadata CRCs, perhaps a decade after that was introduced). This, again, is easier if your backup program emits great big files using linear writes rather than being something that literally mirrors the disk and thus produces massive numbers of tiny files and needs every filesystem feature the source disk uses (that's particularly tricky with Windows backups).
Quote:
Originally Posted by Quoth
Do not leave backup media connected.
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I'd say the opposite: definitely *do* leave backup media connected, because only if you do that can you automate backups (and I run backups *hourly* so I really care about not having to get up every hour to plug in disks!). However, have at least one backup drive which you periodically swap out for a powered-off drive you keep offsite. Then if something (ransomware, lightning) wipes all attached disks you still have that to fall back on. Hopefully this is rare enough that going offsite to pick it up isn't going to be too much trouble: you might well have to do that anyway to replace a lightning-roasted computer...
Quote:
Originally Posted by Quoth
To avoid time delayed ransomeware do two things:
1) Have a test PC that's not on LAN or Internet that you check backup on, that it's not already encrypted.
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Hm that's a good point. Never tried that, but then if I *do* have time-delayed ransomware I think I'd notice it when it detonated for the first time and would intentionally restore (off the offsite disk) from an older backup (my backups are versioned) after flipping the disk to read-only (it's a persistent ATA attribute) on another machine. It's most unlikely ransomware would know to reverse *that*.