71 TiB DIY NAS Based on ZFS on Linux

Re:71 TiB DIY NAS Based on ZFS on Linux by csirac2 on Monday September 01, 2014 @07:59AM (#8252434)

ZFS & btrfs detect and fix silent corruption - where no errors are emitted from the hardware.

I think the pertinent question is: when the filesystem goes to read a 4K block, and one drive's copy of this block in the RAID-1 set is different to its counterpart 4K block on another disk, which one wins?

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Re:71 TiB DIY NAS Based on ZFS on Linux by maaku on Monday September 01, 2014 @12:04PM (#8253488)

I didn't specify RAID-1. RAID-5 or RAID-6 can reconstruct the correct value in a silent fail.

Honest question: how often to drives silently fail? Drives contain per-sector checksums these days, explicitly to prevent this problem.

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Re:71 TiB DIY NAS Based on ZFS on Linux by radiowave on Monday September 01, 2014 @01:22PM (#8253861)

I don't know how often they fail, but I will say that the failures that I hope I never see again (or at least, I hope I never see again outside of a ZFS system) are not drive failures, but those involving intermittent disk controller or backplane faults. In comparison to the chaos I've seen this cause on NTFS systems, ZFS copes astonishingly well.

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