On 26/09/16 10:43, Benjammin2068 wrote:
Hey all,
So the RAID5 which I upgraded to RAID6 was humming along all week just fine (I did the change last weekend) and this weekend I got this:
WARNING: mismatch_cnt is not 0 on /dev/md127
The array seems happy and clean:
You best find out what it is to start with. Example from mine :
brad@srv:~$ cat /sys/block/md2/md/mismatch_cnt
8171392
This is a bad example because it's a RAID10 of 6 SSDs. 3 support zero
after TRIM and the other 3 don't, so after a TRIM of the filesystem the
mismatch count is through the roof.
Unless you are swapping to an array or you have some known issue like
the one I mention above, a mismatch count of non-zero is not good.
I lost most of a RAID6 due to a faulty SIL SATA controller and it was
the high mismatch counts that alerted me. Unfortunately I was about 6
months in and had only checked for the first time. It was silently
corrupting reads under load, and so the read-modify-write cycles were
quietly corrupting the array.
Check the mismatch count, run a "check" on the array and check it again.
If they vary wildly something odd is going on. If they are the same then
you might want to figure out what might have caused it.
Regards,
Brad.
--
To unsubscribe from this list: send the line "unsubscribe linux-raid" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
