Re: Corrupt data - RAID sata_sil 3114 chip

[Robert Hancock <hancockr@shaw.ca>]

Bernd Schubert wrote:
> On Sat, Jan 03, 2009 at 02:53:09PM -0600, Robert Hancock wrote:
>> Bernd Schubert wrote:
>>> [sorry sent again, since Robert dropped all mailing list CCs and I 
>>> didn't notice first]
>>>
>>> On Sat, Jan 03, 2009 at 12:31:12PM -0600, Robert Hancock wrote:
>>>> Bernd Schubert wrote:
>>>>> On Sat, Jan 03, 2009 at 01:39:36PM +0000, Alan Cox wrote:
>>>>>> On Fri, 2 Jan 2009 22:30:07 +0100
>>>>>> Bernd Schubert <bs@q-leap.de> wrote:
>>>>>>
>>>>>>> Hello Bengt,
>>>>>>>
>>>>>>> sil3114 is known to cause data corruption with some disks. 
>>>>>> News to me. There are a few people with lots of SI and other devices
>>>>> No no, you just forgot about it, since you even reviewed the patches ;)
>>>>>
>>>>> http://lkml.org/lkml/2007/10/11/137
>>>> And Jeff explained why they were not merged:
>>>>
>>>> http://lkml.org/lkml/2007/10/11/166
>>>>
>>>> All the patch does is try to reduce the speed impact of the 
>>>> workaround.  But as was pointed out, they don't reliably solve the 
>>>> problem the  workaround is trying to fix, and besides, the workaround 
>>>> is already not  applied to SiI3114 at all, as it is apparently not 
>>>> applicable on that  controller (only 3112).
>>> Well, do they reliable solve the problem in our case (before taking the patch
>>> into production I run a checksum tests for about 2 weeks). Anyway, I entirely
>>> understand the patches didn't get accepted. 
>>>
>>> But now more than a year has passed again without doing anything
>>> about it and actually this is what I strongly criticize. Most people don't
>>> know about issues like that and don't run file checksum tests as I now always
>>> do before taking a disk into production. So users are exposed to known
>>> data corruption problems without even being warned about it. Usually
>>> even backups don't help, since one creates a backup of the corrupted data.
>>>
>>> So IMHO, the driver should be deactived for sil3114 until a real 
>>> solution is found. And it only should be possible to force activate it 
>>> by a kernel flag, which then also would print a huuuge warning about 
>>> possible data corruption (unfortunately most distributions disables 
>>> inital kernel messages *grumble*).
>> If the corruption was happening on all such controllers then people  
>> would have been complaining in droves and something would have been  
>> done. It seems much more likely that in this case the problem is some  
>> kind of hardware fault or combination of hardware which is causing the  
>> problem. Unfortunately these kind of not-easily-reproducible issues tend  
>> to be very hard to track down.
>>
> 
> Well yes, it only happens with certain drives. But these drives work fine on
> other controllers. But still these are by now 
> known issues and nothing is done for that.
> I would happily help to solve the problem, I just don't have any knowledge 
> about hardware programming. What would be your next step, if you had remote
> access to such a system? 

Have you been able to track down what kind of corruption is occurring 
exactly, i.e. what is happening to the data, is data being zeroed out, 
random bits being flipped, chunks of a certain size being corrupted, 
etc. That would likely be useful in determining where to go next..