Based in the linked page, you would need to do something like this:

1) Create a clean array with correctly working disks

2) Tell the underlying block device to pretend there is a read error on
a specific sector of one disk

3) Ask MD to replace the "bad" block device with a "good" one

Do you have a howto on 2,3?

4) See what happens with the BBL

5) Various steps of reading/writing to that specific stripe, and
document the outcome/behavior

or this - how?

6) Replace another drive, and document the results

Hint: there is a block device that could sit between your actual block
device and MD, and it can "pretend" there are certain errors. The
answers here seem to contain relevant information:
https://stackoverflow.com/questions/1870696/simulate-a-faulty-block-device-with-read-errors

As I said, I suspect that if a reproducible error is found, then it
should be easier to fix the bug.

OTOH, you could just remove the BBL from your arrays, and ensure you
create new arrays without the BBL.

Anything better than just "mdadm ... --assemble --update=force-no-bbl"?

Vennlig hilsen

roy
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Roy Sigurd Karlsbakk
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