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I also had two mirrored drives fail simultaneously in my zpool a few days ago. There was nothing on them so I wasn't worried. WD Reds in my case; Using matched
by alias_neo 3y ago
I also had two mirrored drives fail simultaneously in my zpool a few days ago. There was nothing on them so I wasn't worried. WD Reds in my case;
Using matched drives seems to be a very bad idea for mirrors. I'll probably replace them with two different brands.
I also have a matched pair of HGST SAS Helium drives in the same backplane so hopefully I can catch those before they fail too if they're going to go at once, I _do_ have data on those.
- miohtama 3y agoIs there a specific reason why the drives die at the same time? Electricity spike?
- privong 3y agoIf they're ~identical construction and being mirrored so that they have the same write/read pattern history, it could trigger the same failure mode simultaneously.
- dizhn 3y agoMore likely to be from the same bad batch too. There was a post with very detailed comments about this just a few days ago.
- alias_neo 3y agoWhy bad? What's considered a good/bad lifetime for these? Mine had ~43000 power on hours, I don't know if that's good or bad for a WD Red (CMR) drive, but they weren't particularly heavily loaded, and their temps were good, so I'm fairly happy with how long they lasted (though longer would have been nice).
- dizhn 3y agoYou're right it might be a natural end of life that coincides too.
- wruza 3y agoBuying two identical drives has high chances of them being from a single batch, which makes them physically almost identical. It’s a pretty well-known raid-related fact, but some people aren’t aware of it or don’t take it seriously.
- short_throw 3y agoIdentical twins may both die of a heart attack, but not usually at the same time. Normally, failures come from some amount of non-repeatability or randomness that the systems weren't robust to. The drive industry is special (in a bad way) in that they can exactly reproduce their flaws, and most people's intuition isn't prepared for that.
- alias_neo 3y agoIf they're bought together, like mine were, and they have close serials, they've be almost identical; if you then run them in a ZFS mirror like I was, they'll receive identical "load" as well. Since mine had ~43000 hours, they didn't fail prematurely, they just aged out, and since they appear to have been built pretty well, they both aged out at the same time. Annoying for a ZFS mirror, but indicates good quality control in my opinion.
- RealStickman_ 3y agoAlternatively, you can also buy your drives a few months apart to get different batches, most likely.
- alias_neo 3y agoYeah, that's an option; though since my pair failed at once, I need to buy at least two immediately to get the mirror back up.
- hackmiester 3y agoBecause of this, I always buy a different brand as well.
- alias_neo 3y agoAny limitations, or am I good so long as they're the same label capacity? I assume I just lose a few MB or so from whichever is a little larger?