Media Error - Disk 2, No Errors With Disk Doctor

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Jagstyles
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Media Error - Disk 2, No Errors With Disk Doctor

Post by Jagstyles »

I've been getting a message recently that the 2nd disk in my RAID 1 setup has a "Media Error". I run the disk doctor on the disk and everything checks out fine. Does anyone have any ideas/suggestions how I can resolve this issue or what the problem might be?
Jagstyles

Re: Media Error - Disk 2, No Errors With Disk Doctor

Post by Jagstyles »

So just to follow-up on this, I went into the log of my NAS and noticed the following error:

"There is a media error on sector 11698440896 on the slot 2 disk"

However, when I run the disk doctor and scan the entire drive, it reports not finding any bad blocks or issues with the drive. Any ideas or suggestions?
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orion
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Re: Media Error - Disk 2, No Errors With Disk Doctor

Post by orion »

mm... interesting. 3 possibilities: 1. fake error log message (disk is in good state). 2. fake disk doctor action (disk is in bad state). 3. recovered by re-writing data (disk is bad, but recovered).

I think you can use "dd" command (ssh login with root) to verify this sector. If all good, that might be case 1 or case 3. If it's bad, that should be case 2.
Jagstyles

Re: Media Error - Disk 2, No Errors With Disk Doctor

Post by Jagstyles »

orion wrote:mm... interesting. 3 possibilities: 1. fake error log message (disk is in good state). 2. fake disk doctor action (disk is in bad state). 3. recovered by re-writing data (disk is bad, but recovered).

I think you can use "dd" command (ssh login with root) to verify this sector. If all good, that might be case 1 or case 3. If it's bad, that should be case 2.
What would be the exact command for running DD on the second drive? I'm able to login but unsure on the command I should use. Also, there's an option in my RAID1 setup to REMOVE when I select the VOLUME. Will this impact the data on both drives or simply disable the RAID configuration? I was thinking I could temporary remove RAID, format the 2nd drive which is the one causing me issues and then setup the RAID configuration again.

Any thoughts?
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orion
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Re: Media Error - Disk 2, No Errors With Disk Doctor

Post by orion »

Jagstyles wrote: What would be the exact command for running DD on the second drive? I'm able to login but unsure on the command I should use. Also, there's an option in my RAID1 setup to REMOVE when I select the VOLUME. Will this impact the data on both drives or simply disable the RAID configuration? I was thinking I could temporary remove RAID, format the 2nd drive which is the one causing me issues and then setup the RAID configuration again.

Any thoughts?
No, you should not remove volume. That will delete your data. However you can remove the bad disk out, then insert it back to NAS (when NAS is still working). NAS should re-sync data to "the bad disk".

I don't know which disk in your configuration. You'll need to find out which device file under Linux (/dev/sda, /dev/sdb, ...). As an example (/dev/sda), you can try command:

Code: Select all

dd if=/dev/sda of=/dev/null bs=512 count=1 skip=11698440896
Jagstyles

Re: Media Error - Disk 2, No Errors With Disk Doctor

Post by Jagstyles »

orion wrote:
Jagstyles wrote: What would be the exact command for running DD on the second drive? I'm able to login but unsure on the command I should use. Also, there's an option in my RAID1 setup to REMOVE when I select the VOLUME. Will this impact the data on both drives or simply disable the RAID configuration? I was thinking I could temporary remove RAID, format the 2nd drive which is the one causing me issues and then setup the RAID configuration again.

Any thoughts?
No, you should not remove volume. That will delete your data. However you can remove the bad disk out, then insert it back to NAS (when NAS is still working). NAS should re-sync data to "the bad disk".

I don't know which disk in your configuration. You'll need to find out which device file under Linux (/dev/sda, /dev/sdb, ...). As an example (/dev/sda), you can try command:

Code: Select all

dd if=/dev/sda of=/dev/null bs=512 count=1 skip=11698440896
I've ended up buying a replacement drive because I noticed more and more bad sectors on Disk 2 of my RAID1 configuration, so I'm assuming it's only a matter of time before it dies completely. So to replace this bad drive, while the NAS is running, I can simply swap out the old drive with the new drive and the NAS will do it's thing? I just want to make sure I don't screw anything up when doing this swap.

Thanks
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orion
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Re: Media Error - Disk 2, No Errors With Disk Doctor

Post by orion »

Jagstyles wrote: I've ended up buying a replacement drive because I noticed more and more bad sectors on Disk 2 of my RAID1 configuration, so I'm assuming it's only a matter of time before it dies completely. So to replace this bad drive, while the NAS is running, I can simply swap out the old drive with the new drive and the NAS will do it's thing? I just want to make sure I don't screw anything up when doing this swap.

Thanks
Yes. BUT you need to make sure the new disk size >= the old disk size. Then, simply replace the old disk with the new one when NAS is working.
Jagstyles

Re: Media Error - Disk 2, No Errors With Disk Doctor

Post by Jagstyles »

Thanks, I was able to replace the defective drive. Quick question, is there any way to add a 3rd drive as a stand alone disk within the NAS and format it once in the NAS? I have put a 3rd drive in that is not part of the RAID and want to use it as additional storage for other things. However, I don't see anyway to access the drive to add files/folders nor can I seem to format it.

Any ideas?
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orion
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Re: Media Error - Disk 2, No Errors With Disk Doctor

Post by orion »

Jagstyles wrote:Thanks, I was able to replace the defective drive. Quick question, is there any way to add a 3rd drive as a stand alone disk within the NAS and format it once in the NAS? I have put a 3rd drive in that is not part of the RAID and want to use it as additional storage for other things. However, I don't see anyway to access the drive to add files/folders nor can I seem to format it.

Any ideas?
Well, you'll need to create another volume first, said volume-2 (ADM web -> Storage Manager). Then create shared folders on that volume and assign access rights (ADM web -> Access Control).
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