Windows 7 - Data errors on HP Mydrive NAS

Asked By Pavel A.

17-Jan-10 09:02 PM

I have a strange issue with a HP Mydrive "World edition" connected to
ethernet.
Files copied to this drive sometimes get corrupted, in a very specific
pattern.

We cannot reproduce this corruption with smaller files, less than 2 MB, but
with
files > 20 MB it occurs in 80% of copies.
I copy the files by drag & drop from Explorer, or by copy / v command,
results are same. More over, copy /v does not find any error.
Then I run fc /b <copy> <original>  and it finds differences.
In a ~ 20 MB file, there are few  bytes (1 to 6)  with one bit (same in all
cases) stuck in "1".

The drive sits in a conditioned server closet.

What can cause this? Should I look for electrical interference, magnetic
field and so on?

Can you recommend a good disk test for revealing data corruptions?

Regards,
-- pa

19-Jan-10 03:37 PM

Ethernet is a serial medium that is well checksumed, so it is unlikely
that the network is causing this problem. My bet would be a loose
data bit connection somewhere between the NIC and the hard drive inside
the NAS.  It sounds like you need to replace your NAS.

HTH,
John

19-Jan-10 07:15 PM

It could be RAM somewhere in the path to the platters. Say, the cache
RAM on the hard drive inside the NAS itself could be bad. Perhaps a
hard drive diagnostic, and slaving the drive to an existing computer,
would make it possible to test for that. The NAS itself may be a
small computer, with its own RAM, which would give another place
for problems to occur. Robust designs would do self-test at
startup and not start if a problem was detected. Or, to give better
run-time protection, having ECC on RAM would help detect things
such as stuck bits in any RAM being used.

Paul

22-Jan-10 07:07 PM

Thanks. This kind of confirms my thoughts. The errors occurs on the path
from RAM (cache) to the disk drive, otherwise copy /v would fail earlier.
But OTOH,  we consumers like our CE stuff to be dirt cheap... so we get what
we paid for.
--pa