Re: Huge values of mismatch_cnt on RAID 6 arrays under Fedora 18

[Wolfgang Denk <wd@denx.de>]

Dear Piergiorgio Sartor,

In message <20130128204422.GA14115@lazy.lzy> you wrote:
>
> It could still be the data is as it was written,
> but, for some reasons I could not imagine, the
> parities (both) are not correct.

This is what I think at the moment, as all my samples of data so fare
looked ok.

> This could be in case of some software bug, which
> would be quite a surprise, I must say.

Indeed.  Guess how I feel...

> Still, would be nice to check if the whole array
> is it this state or if, sooner or later, some
> knwon slot (with error) is found somewhere else.

Checks still running.  I see two things:

- on the array where I was running "repair" before, raid6check reports
  no errors so far - but still there is a mismatch_cnt = 362731480
  raid6check is still running.

- on the second machine, I have 558579 lines out output, 176 of which
  are errors of type "Error detected at : disk slot unknown"; no other
  errors reported so far.  raid6check is still running.

- on the third machine, I have 5512894 lines out output, 1599431 of
  which are errors of type "Error detected at : disk slot unknown"; no
  other errors reported so far.  raid6check is still running.

This smells really bad as if parity computation was broken...

OK, add more hardware details...

A: Supermicro X8SAX mainboard, Core i7 CPU 950 @ 3.07GHz, 24 GB RAM
H: Supermicro X8ST3 mainboard, Xeon CPU W3565  @ 3.20GHz, 24 GB RAM
X: Supermicro X8SAX mainboard, Core i7 CPU 950 @ 3.07GHz, 24 GB RAM


Best regards,

Wolfgang Denk

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