Emergency: Backup Hard Drives failed


I’ll make it short:
Apparently relying on a 4-way mirror for my most important backups wasn’t enough. Every single hard drive from the 4-way mirror failed(?) simultaneously. They aren’t even recognized by fdisk anymore.
Because this sounds so incredible to me as well, I question if this could happen the way it seems it happened.

I’m all good as long as I can clone or access hard drives at all. If they don’t even show up with fdisk, it’s another story.

  • I excluded adapters and cables as a source of error. Everything that was connected to the hard drives works flawlessly with a different HDD pool.
  • The 4-way mirror was achieved with ZFS.

Does anyone have suggestions?

Actually the check per single drive did not go smoothly. Only one hard drive is broken, after all. Seems like the mirror held its promise.

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Glad to hear your problem was solved @Akito. But for some of us less techincial, could you explain a 4-way mirror (is it 4 disks all kept in sync?) and was was it only one HDD that went bad? And replacing the bad HD solved your problem. The software re-sync with the new disk drive.

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I think following resources should help you understand:

A mirror of two or more devices. Data is replicated in an
identical fashion across all components of a mirror. A mirror with
N disks of size X can hold X bytes and can withstand (N-1) devices
failing before data integrity is compromised.

From https://illumos.org/man/1M/zpool

After all, it indeed was only one HDD that went bad.

Did not find a replacement yet, but I’m working on it. Maybe I will change the setup of this mirror entirely, as I use a new Backup-of-the-Backup system now, anyway.

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Thanks for the Ton of info. I was not looking to install this type of configuration on my home PC. I know how Raid and a mirrored disk works. I had not hear of a 4-way mirror. I was thinking maybe it was just 3 copies of the same disk meaning you had 4 disks with the same info on them. Maybe that’s too simple of a way to thinking of it. And of course, if one disk went bad, no problem. You still have original disk plus 2 copies.