RAID problem : mismatch_cnt is not 0

[Bob Sauvage]

  Hello *,

I received this email :

    /etc/cron.weekly/99-raid-check:

   WARNING: mismatch_cnt is not 0 on /dev/md0


_When I look the log :_

Oct 17 04:22:02 xxx kernel: md: syncing RAID array md0
Oct 17 04:22:02 xxx kernel: md: minimum _guaranteed_ reconstruction speed: 1000 KB/sec/disc.
Oct 17 04:22:02 xxx kernel: md: using maximum available idle IO bandwidth (but not more than 200000 KB/sec) for reconstruction.
Oct 17 04:22:02 xxx kernel: md: using 128k window, over a total of 488231296 blocks.
Oct 17 07:51:00 xxx kernel: md: md0: sync done.


_The count :_

cat /sys/block/md0/md/mismatch_cnt
1664


_I launch this action :_

echo repair>>  /sys/block/md0/md/sync_action


_But I seen :_

http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=405919


   md/sync_action
       This can be used to monitor and control the resync/recovery
       process of MD. In particular, writing "check" here will cause
       the array to read all data block and check that they are
       consistent (e.g. parity is correct, or all mirror replicas are
       the same). Any discrepancies found are NOT corrected.

       A count of problems found will be stored in md/mismatch_count.

       Alternately, "repair" can be written which will cause the same
       check to be performed, but any errors will be corrected.


How can I fix this problem if the "repair" command do not correct this 
error ?

Thanks in advance,

Bob !