Random bit flipping in the files / Corrupted files

[petar.dugic]

I've been doing some comparing of the files (source) from my Windows machines with the files I copied on the DS212j (destination). Some of the files were changed. From 20000 files (photos) about 30 were changed. No error message appeared at all as I was doing file copy !!!!! Scary!

After logging into DS via telnet and using
openssl dgst -sha1 <file>
on one of the changed files I noticed that sometimes the sum matches and sometimes it doesn't.
For example for the first 20 minutes I got the correct sha1 value but after that the value was wrong !!!! File was not moved, deleted or modified at all. So it's a kind of random issue.

S.M.A.R.T test didn't show any problem.

How can I be sure is it a HDD or DS212j?

HDD is officially compatible: Western Digital WD20EARS Caviar Green 2TB

Appriciate your help.

[petar.dugic]

I moved the HDD to the computer, reformated it but still using ext4.
Everything seems to work perfectly in the computer.
I copied a lots of Gigabytes around and there is not a trace of corrupted files.
Seems to be a Synology problem !!!

Anyone else has similar problems?

[petar.dugic]

After getting my Synology 212j replaced everything is working perfectly.

So it was a hardware problem of the Synology NAS.

Very bad thing is that there are no error messages at all.
I discovered the problem luckily soon after buying the device.

Advice for everybody ... test the files in your storage.

Regards

[me.anon]

I'm afraid you are not alone. I've had a similar "Quality" problem with the DS212J. See my experience here ...
http://forum.synology.com/enu/viewtopic.php?f=49&t=44194

[petar.dugic]

At least you had some visible errors ...

In my case everything appeared perfect.

Again - advice to everyone - compare the files you upload to the Synology with some kind of CRC, MD5 or SHA1 checker.

[JohnEvo]

I seem to have the same problem with my new DS212j. TeraCopy (great program!) copied my files just fine, but tons of errors were returned when the copy was verified. Some which were verified would fail after being checked again. However, some files seemed to always fail to copy, so it may not be random.

Still waiting for Synology to respond to my trouble ticket...

[ase09234j]

This is happening to me too. It seems particularly bad when copying large (5+ GB) .vdi files. I've seen several cases where the MD5 of the original file is not the same as the MD5 of the file on my DS212J. In fact, I can calculate the MD5 on the Synology multiple times and get multiple results. How messed up is that! Also, the mirrored drives pass SMART tests. I have DSM 4.0. This thing is going back to Amazon and I'm going to purchase something stable. File integrity is table stakes, how can they have messed this up??