Re: mismatch_cnt again

Eyal Lebedinsky
2009-11-07T07:49:33Z

Berk,

I am not sure that I understood your response. As I explained, I did start with
a clean slate: New hardware, new system install and a zero mismatch count.

After three months the weekly 'check' detected a mismatch. During this period
there were no hardware errors reported on this system. smart shows no issues
with the disks.

You ask "Do you have any logs showing these strangenesses?" and I have none,
just a non-zero count from a raid check.

About cables: Does the sata protocol have checksums on the transactions?
I always assumed so but never looked into it.

I also ran a long memtest before commissioning the new hardware.

cheers
Eyal

berk walker wrote:
> Eyal Lebedinsky wrote:
>> For years I found the mismatch_cnt rising regularly every few weeks
>> and could
>> never relate it to any evens.
>>
>> I since replaced the computer, installed fedora 11 (was very old debian)
>> and only kept the array itself (ext3 on 5x1TB raid5). I had the raid
>> 'repair'ed to get it to mismatch_cnt=0.
>>
>> I thought that I saw the last of these. I had a good run for almost three
>> months, then last week I saw the first mismatch_cnt=184. It was still so
>> on this weekly 'check'.
>>
>> I cannot see any bad event logged.
>>
>> Are there situations known to cause this without an actual hardware
>> failure?
>> I know that this came up in the past (often) but I see little recent
>> discussion and wonder what the current status is.
>>
>> For the last 6 weeks (my uptime) the machine runs
>> 2.6.30.5-43.fc11.x86_64 #1 SMP
>>
>> The raid holds data (no root or swap) used mostly as DVR (nothing heavy).
>> smartd checks each week and so far no errors. The disks are modern 1yo
>> "SAMSUNG HD103UJ".
>>
>> TIA
>>
> >I< am not quite sure what you are reporting as a problem here, sir.
> "new computer".. drives ~ 1 yr old...mismatch..I know.. seems like
> things just want to die ..
> Do you have any logs showing these strangenesses?
>
> I suggest - start off with SOMETHING at zero point, then track what
> changes... oh BTW did you change the drive cables?
>
> Best to you,
> b-

--
Eyal Lebedinsky (eyal@eyal.emu.id.au)