Re: Data corruption

["Jeffrey V. Merkey" <jmerkey@wolfmountaingroup.com>]

paul wrote:

If you remove memory and it goes away it probably is related to ECC 
issues.  Replace the upper 2GB of memory -- it appears to
have a defect.  If it persists after replacing the memory, then it may 
be software related.   Doesn't sound like it though.  Sounds like the
same problem I have seen.    

Jeff

>Hi, thank you for your answer, actually I removed 2Gb of physical memory and 
>the problem gone away .. but my system needs 4Gb.
>
>I reproduce it under Xen and without xen (on a standard kernel) I can't tell 
>you how mutch difference I have betwwen files, regarding a 4 month system 
>running on these condition, I think the number of errors are rare but 
>existing, during my tests with 100M files I did not get a lot of error, so we 
>can assume 2 or 3 bytes in error in 300M files... (expectation)
>
>I try to avaoid it by disabeling memory relocation on my MB ... in that case 
>the system only detect 2.8G (and Linux too), The probem still there.
>
>It seems to be based on an Asus P5B-VM problem as this one have a lot of with 
>4Gb... But it should be certified on Windows up to 8Gb... (but I did not have 
>that strange OS to check). So a workaround should exists.
>
>
>Le mercredi 8 août 2007 01:57, vous avez écrit :
>  
>
>>paul wrote:
>>    
>>
>>>Since 2-3 month I have some random data corruption on my Linux server,
>>>after checking disks independently (i'm using raid1on 2 sata disk, the
>>>problem is the same w/o raid) and memory, hardware simce to be out of
>>>cause...
>>>
>>>Here is my problem:
>>>=> head --bytes=300m  /dev/urandom > test
>>>=> for i in `seq 0 9` ; do cp test test$i ; done
>>>=> md5sum test*
>>>I got :
>>>014666c728c9e3b8299579fae499864a  test
>>>014666c728c9e3b8299579fae499864a  test0
>>>333fd93d093ac612cd8d5f65628f734e  test1
>>>1ab6ee68c6a7d9ff5a05f9d63f0f6df6  test2
>>>96e96483e3175a59c9c05b6720514e1e  test3
>>>014666c728c9e3b8299579fae499864a  test4
>>>b24dbccc9f4831f8825ab4a55a3be4aa  test5
>>>8493efc9c14e4b5c162ac23696fbc16a  test6
>>>6a5f4301f66d0379049d79d0e14e2a87  test7
>>>2c81cfa1c3a03aba134574922ee5d75c  test8
>>>2ea15c8392bfd0123472a80125bb3abe  test9
>>>
>>>^^^ that sounds really bad for my data :(
>>>      
>>>
>>It does indeed.  Can you try comparing the data to see precisely how much
>>differs between the versions?  md5sums don't distinguish between a
>>single-bit error and a block or page-sized error, but the distinction is
>>critical in determining what broke.
>>
>>Can you reproduce this on a recent upstream baremetal (non-Xen) kernel?  If
>>so, does it go away when you boot with mem=3000M?
>>
>>	-- Chris
>>    
>>
>
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