On Tue, February 24, 2009 7:19 am, Piergiorgio Sartor wrote:

Hi,

quoted

What exactly do you mean by "check".

If you mean "look in /sys/block/md0/md/mismatch_cnt", then that is
exactly what I would expect.  The resync found some differences, just
as you would expect it to, and reported them.

However if by "check" you mean:
  echo check > /sys/block/md0/md/sync_action
  mdadm --wait /dev/md0
  cat /sys/block/md0/md/mismatch_cnt

yes, that is what I mean.
I start the check _after_ the resync.

Actually, maybe this is not correct, I keep running
something like:

watch cat /proc/mdstat /sys/block/md2/md/mismatch_cnt

So I can see real-time, so to speak, the check
progress and the mismatch count, just to have
an idea on where, on the RAID, the mismatches
could be located.

Is this a problem?

No, that isn't a problem.

quoted

then I would not expect any mismatches, and the resync should have
fixed them.

If it is the later, that is a real concern and I will need to look into
it.
Please let me know exactly which kernel version and mdadm version you
are running.

It is an up-to-date Fedora 10, i.e. kernel-2.6.27.15-170.2.24.fc10
and mdadm-2.6.7.1-1.fc10.

I might have found something.  If the bitmap chunk size is smaller than
the raid10 chunk size, and the first bitmap chunk in a raid10 chunk is
clean, it might be skipping the remaining bitmap chunks in that
raid10 chunk.

Can you please show me "--examine" and "--examine-bitmap" of one of the
devices in your array please.

Thanks,
NeilBrown