NETGEAR is aware of a growing number of phone and online scams. To learn how to stay safe click here.
Forum Discussion
BitRot Protection Failure - Anything To Be Done?
12:37:25 AM 01/21/2015
Bit rot protection has detected a silent error within /data/FileHistory/Home/C52893-G/Data/$OF/18143/18144 (2015_01_15 11_11_06 UTC).jpg on /dev/sdc3 and cannot correct the error.
My new RN104 has been online only three weeks; I'd hoped to go a long time before seeing something like this. In fact, I wouldn't have expected to see it at all. Clearly BitRot Protection isn't the failsafe I'd thought it was.
Not that I'm too awfully concerned in this particular instance, mind you. The file itself is inconsequential. Upon visual inspection in a graphics editor there doesn't seem to be anything wrong with it at all. In this case at least, it certainly isn't worth going to the trouble to find it and restore it from backup.
I'm just wondering how serious this is in general; is it a sign of a deeper problem; might it occur often; can anything be done to prevent it; can anything be done to fix it after the fact (beyond restoring from backup).
Note that it happened about twenty minutes following a resync completion after replacing a 2TB drive whose sectors were failing.
Thanks,
Jeff Bowman
Fairbanks, Alaska
18 Replies
Replies have been turned off for this discussion
mdgm wrote: The WD20EARX is not on the compatibility list (http://kb.netgear.com/app/answers/detail/a_id/20641). I can see that one of your remaining WD20EARX has a huge load cycle count and the other is fairly new and looks to be heading the same way. You may wish to alter the WDIDLE3 timer interval for these disks.
OK, I'll have a look at that. In which log file did you see this data?mdgm wrote: I think it's quite possible the drive selection played a part in the failure here.
That's reassuring, in a strange sort of way.mdgm wrote: It would be good if you could replace your remaining WD20EARX disks with 4TB WD RED disks when you get the chance (one at a time, wait for resync to complete before you replace the next disk).
Thanks... I've just replaced the older of the two remaining 20EARX drives with a 40EFRX drive (one that's been through the Amazon gauntlet, but that passed the Data Lifeguard Quick Test at least). It's resyncing now.
At some point in the near future I'll likely take WD up on their offer to RMA these drives even in the face of any potential damage being Amazon's fault.mdgm wrote: RAID, Bitrot protection, unlimited snapshots and anti-virus are great features that help to protect your data but they can never replace the need for backups. Important data should never be trusted to just the one device. There are things like multiple disk failures, fire, flood and theft that can happen.
I'm starting to take this mantra more seriously than I have in the past. For this I credit the good folks on this forum and their repeated helpful reminders.
Thanks,
Jeff Bowman
Fairbanks, AlaskaStephenB wrote: On other threads Jeff indicated that he is only using the EARX drives temporarily - WDC Reds or Pros are in his future.
Thank you for saying so.StephenB wrote: fwiw, I'd still say this is worth looking at.
I'm all for it. Next steps?
Thanks,
Jeff Bowman
Fairbanks, AlaskaSkywalker wrote: Are you able to open the file? If so, does it look normal? Fortunately, it should be easy to spot corruption since it's a JPEG image.
It's small and heavily pixelated, but here it is just in case: click here.
Spot anything?
Thanks,
Jeff Bowman
Fairbanks, AlaskaSkywalker wrote: It's certainly not an established fact that we have a false positive. That's what I'm trying to find out.
Anything I can do to help, let me know.
Thanks,
Jeff Bowman
Fairbanks, Alaska- Thanks for working through this. Do you have the original source of that file? Maybe we could checksum both files.
Also, do you get alerts every time you read that file? If you reboot the NAS and open the file again, do you get a fresh alert? Skywalker wrote: Thanks for working through this. Do you have the original source of that file? Maybe we could checksum both files.
I ran an MD5 on the three copies: 1) The original, 2) The version on the NAS and 3) The version I copied from the NAS to OneDrive (linked earlier in this thread).
All three are identical.Skywalker wrote: Also, do you get alerts every time you read that file?
No.Skywalker wrote: If you reboot the NAS and open the file again, do you get a fresh alert?
No.
So we seem to have a false positive. Which, as StephenB points out, isn't the best of situations either.
Thanks,
Jeff Bowman
Fairbanks, Alaska
There are two basic scenarios I see:InteXX wrote: So we seem to have a false positive. Which, as StephenB points out, isn't the best of situations either.
-a "real' false positive (the file was never corrupted)
-a "pseudo" false positive (the file was corrupted, and was properly fixed. But the error message saying "I can't fix it" was still logged).
It might take more reports/additional logging for Netgear to sort it all out. The good news is that whatever went wrong in your case, it did not result in file corruption. And the issue resolved on its own (no more checksum errors, you can access the file, etc).
Of course for us users, the message remains that backups are needed for lots of reasons.StephenB wrote: It might take more reports/additional logging for Netgear to sort it all out.
Skywalker's working on it. I opened a port for him and he said he found what he needed to investigate further. I'll report what I know to this thread as the information comes in.StephenB wrote: The good news is that whatever went wrong in your case, it did not result in file corruption. And the issue resolved on its own (no more checksum errors, you can access the file, etc).
Yes, but it's bittersweet. I only wish the file had been more important, so I could be more relieved ;)StephenB wrote: Of course for us users, the message remains that backups are needed for lots of reasons.
Lots.
Thanks,
Jeff Bowman
Fairbanks, Alaska
NETGEAR Academy
Boost your skills with the Netgear Academy - Get trained, certified and stay ahead with the latest Netgear technology!
Join Us!
