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Moving large amounts of data between HDDs... CRC "fail"?

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Sakura90:
Hi

Seeing the great success that my other thread was... let's make a new one :P


I've experienced this for a long time now. It happens only when I move large amounts of data (around 1TB) from one HDD to another. As I have everything formatted in the usual "anime fashion" [Group/Source] Title [xxxxxxxx], after copying I do a full CRC check of all files. And the results often have one CRC mismatch. I don't recall seeing more than 1 fail per "batch". It's only one of the files, always a large one (10-20GB).

But it isn't a "fail" really. After the whole check, I go check again and again the "failed" file. But always after that the CRC matches. I even check a couple of times after using the drive everyday. The file never fails again. Nor does anything else.


This only occurs in the case I described, it can be from a 500GB to more than 1TB copies. It's never with a less amount. I always keep backup of every single bit I have, and despite those fails, I never lost anything. It's a "one time" fail that never "fails" again.

And I don't remember well now, but I could had had the same "issue" only by doing a hash check of all files in a 2TB drive, without anything new being copied. I should do a full check these days overnight and see what happens :P

Why does that happen? I've seen sometimes the HDDs specifications that they say something like a failure in 10^50 bits (to say a number). Does that have something to do? But the writes never fail actually, all files check ok. Even if one seems to fail, it passes if I check again and again.

Maybe it's a bug in the program? I use AnimeChecker, as it's the only one I know that can read the CRC to check from filenames.



It's weird. Any ideas? As this happens usually and I never really lost anything, I just check the failed file again and then sleep in peace :P. But curiosity kills me <.<

Btw, this happen while using the HDDs in a dock, external enclosure or even as regular internals. Drives are all "green" though, WD Green and Samsung Spinpoint F4 are what I use.



P.S.: Anyone knows of another program that can calculate a CRC and check it against the number in the filename?

Freedom Kira:
I use RapidCRC. It's never given me problems, but at the same time I haven't used it extensively, and definitely not for so many files at once.

lapa321:
It's normal. Our anime just uses so much data that we easily blow through any kind of error margin or data safeguards built into our systems.

Someone recommended FastCopy, it's a pretty good utility that's got a verify option.

Big Teeth:
But better run a memorychecker for 24 hours on your system.
Or remove half of the memory from your system.
Do your copying around. Still troubles?
Swap the half memory and copy around again.

Have been there with a 3 GB RAM system. Troubles all over the place.
Using only 1 or 2 GB and everything went fine.

It turns out your files are oke, so why rerererecheck them again? :S

rkruger:
Sounds like a memory problem to me.
As Big Teeth suggested, you should run a program to check the memory.
I suggest booting Memtest86 (http://www.memtest.org/) from a CD.

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