In my not-so-humble opinion, the bug is the existence of the BadBlocks
feature.  Once a badblock is recorded for a sector, redundancy is
permanently lost at that location.  There is no tool to undo this.

I strongly recommend that you remove badblock logs on all arrays before
the "feature" screws you.

I think it has screwed me a bit already, but then, I didn't check until recently. I didn't even know about this "feature". But doesn't help much when those "badblocks" are recorded already. What would be the official way to remove them apart from rebuild the whole array?

A friend of mine wrote a thing in python to remove the badblocks list from an offline array. I haven't dared to test it on a live system, but apparently it worked on his (5 drives in RAID-5 IIRC with three of them showing a list identical of badblocks). You can find the code here https://git.thehawken.org/hawken/md-badblocktool.git

Vennlig hilsen

roy
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Roy Sigurd Karlsbakk
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http://blogg.karlsbakk.net/
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