Re: single bit errors on files stored on USB-HDDs via USB2/usb_storage

[Robert Hancock <hancockr@shaw.ca>]

Matthias Schniedermeyer wrote:
> Hi
>
>
> I'm using a Bunch auf HDDs in USB-Enclosures for storing files.
> (currently 38 HDD, with a total capacity of 9,5 TB of which 8,5 TB is used)

All the same enclosure type?

> This time i kept the defective files and used "vbindiff" to show me the
> difference. Strangly in EVERY case the difference is a single bit in a
> sequence of "0xff"-Bytes inside a block of varing bit-values that
> changed a "0xff" into a "0xf7".
> Also interesting is that each error is at a 0xXXXXXXX5-Position
>
> Attached is a file with 5 of the 6 differences named 1-5. Of each of the
> 5 2x3 lines-blocks the first 3 lines are the original the following 3
> lines contain the error in the middle row 6th value.
>
> NEVER did i see any messages in syslog regarding erros or an aborting
> program due to errors passed down from the kernel or something like that.

The fact that the corruption seems data dependent would seem to me to 
point to some kind of hardware problem. I would tend to suspect the 
USB-to-IDE converters in the enclosures as being faulty or something 
like that..

--
Robert Hancock      Saskatoon, SK, Canada
To email, remove "nospam" from hancockr@nospamshaw.ca
Home Page: http://www.roberthancock.com/

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