Apparently spurious ZFS CRC errors (was Re: ZFS data error without reasons)

army.of.root army.of.root at
Wed Mar 25 13:46:31 PDT 2009

Alexey Shuvaev wrote:
> On Wed, Mar 25, 2009 at 07:38:32PM +0100, Bernd Walter wrote:
>> On Wed, Mar 25, 2009 at 06:04:08PM +0000, Mark Powell wrote:
>>> On Wed, 25 Mar 2009, Bernd Walter wrote:
>>>> On Wed, Mar 25, 2009 at 03:21:28PM +0100, Alexander Leidinger wrote:
>>>> I wouldn't be surprised if the problem is in the drive firmware.
>>>> Preread and wc both have the potential to put a lot load to the drives
>>>> and can trigger bugs that otherwise wouldn't matter.
>>> I've emailed WD support for more info. Not expecting much though.
>>> From reading other threads on these Green Power drives them seem rather 
>>> crap. This is my model and firmware:
>>> There's some head park problem too, but with 5s ZFS sync I don't think it 
>>> applies in this case:
>>>> I also have a system running WD drives and ECC RAM which show CRC errors
>>> >from time to time, while all other systems have no CRC problem at all.
>>> Interesting. Are those CRC problems with WC on or off?
>> WC is on, prefetch is off, but only because it had bad performance with
>> MySQL.
>> Drives are <WDC WD3200AAKS-00SBA0/12.01B01> Serial ATA II
>> I don't know if it is with the drives, but other reasons are less
>> likely in my opinion.
>> The system is located in a data center and since I only get a few errors
>> I decided to live with it and not to debug it further.
> Hello!
> Me too...
> I don't use zfs, just ufs2 + soft updates, but I see sometimes rather
> heavy data corruption (most often on / filesystem).
> No kernel messages, I can shut down the system successfully just
> to find the remnants of filesystems on the next boot.
> It doesn't happen often, I think compiling ports in a jail + some
> activity in the host increase the probability of a failure.
> The drive is:
> ATA channel 3:
>     Master:  ad6 <WDC WD5000AAKS-00C8A0/12.01C02> SATA revision 2.x
> hw.ata.wc=1 (default)
> Alexey.

Hi :)

Damn f**k ! - I just bought WD harddrives for my Workstation...

is there any way to detect silent data corruption without ZFS ?

best regards

PS: Thanks for all your work, I'm looking soo forward to 8.0 I cant even tell 
you how much :)

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