Offline drives fail at least as often (and probably more often) than hot drives.
This is largely from anecdotal experience, but also from an article written by a drive engineer 20+ years ago.
And it matches my own experience with complex mechanical systems I’ve maintained. Lubricants are a major problem for mechanical systems that sit unused - best practice is to either run them on a cycle, or be prepared to disassemble, clean, and re-lubricate after a period of non-use.
Even tape has risk when sitting unused.
Multiple copies on live systems with error detection/correction storage systems is where it’s at.
In the last year I’ve seen bit flips on data that’s stored in 3 locations, because my master data store doesn’t reside on a robust error correcting file system - and that’s at measly single-digit terabytes.
LincolnsDogFido@lemmy.zip 21 hours ago
Right, but this is for archival storage, so if the drive fails, the data is still present on the physical platters. All you need to do is repair the drive. Am I mistaken?
AnyOldName3@lemmy.world 19 hours ago
Hard drives store data as magnetic fields, and also contain powerful magnets to allow the read head to move around quickly, so there’s a decently high risk of damaging data when transplanting a platter to a different drive or replacing components within a drive. Also, even if that doesn’t happen, modern drives really need to be opened in a clean room as the head floats a very small distance above the platter so the tiniest bits of dust can wreck the surface of they end up in the gap. For some drives, even that isn’t enough as they don’t contain air, they contain helium. Of you want to be sure data remains intact, opening the drive should not be part of your plan. It’s only a good idea as a last resort when you don’t have a more conventional way to recover something.
LincolnsDogFido@lemmy.zip 19 hours ago
i didn’t realize it was such a delicate process. I knew catastrophic failures could cause data loss. Especially while reading or writing, but I didn’t know that could be the case just opening and repairing the drive. TIL
a_non_monotonic_function@lemmy.world 17 hours ago
Yup. Shit has to be aligned perfectly. Just a head transplant has someone putting a specialized comb into the diner drive to hold things perfectly in place to be moved.
And some drives or even filled with inert gasses to pump back in.
The process is specialized and to non-trivial for the average person.