Dear Piergiorgio,

In message [ref] you wrote:

If all error report by raid6check, on the three
systems, are "unknown", then it seems to be a
software problem.

I think we can be pretty sure of this now.  For a test, I installed a
vanilla mainline Linux kernel (v3.8-rc5) on the affected machines.

A "check" operation showed no more problems, but "raid6test"
still reported a large number of errors like these:

...
P(4) wrong at 10291
Q(5) wrong at 10291
Error detected at 10291: disk slot unknown
P(3) wrong at 10292
Q(4) wrong at 10292
Error detected at 10292: disk slot unknown
P(2) wrong at 10293
Q(3) wrong at 10293
Error detected at 10293: disk slot unknown
...

After running a "repair" on the array, both "check" and "raid6test"
would not report any further issues.

I'll continue to watch this for a while, but I think I will not
"update" to a Fedora kernel for some time...

Best regards,

Wolfgang Denk

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