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rescue videofiles on defect sectors?

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(@ffuchs)
Active Member

hi,

we have an OWC Express 4M2 with four sandisk extreme pro m.2 nvme 3d 2TB hard disks.

unfortunately all four drives have i/o-errors, I copied with carbon copy cloner everything to an usb-drive, but ccc could copy only 3 TB of 5 TB - the rest are obviously files, that are on defect sectors and therefore ccc skipped them.

I opened a videofile, that ccc couldn't copy and I could play it for 20 minutes, until I get to a point in the videofile, that is on a defect sector.

so it's unfortunate, that we lose for example a 500gb videofile because of one defect sector. so I would like to ask, is there any possibility to copy this file and use the videofiles without the defect sectors? I'm no videoexpert, but I think, this will be difficult, especially to get the video-area after a defect sector because most videoformats needs information from earlier parts of the videofiles, but perhaps in some videos the error is at the end of a video, so we could use at least the video-footage before an error.

many thanks,

ferdinand

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Topic starter Posted : 09/02/2021 2:01 am
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(@softraid-support)
Member Admin

This is unfortunate. I am not sure. I am not that knowledgeable on this subject.

Are all 4 of the drives defective, or just one?

You may be able to clone the eraw devices using terminal, and reduce the faulty sections to 512byte chunks. I can help with that. If you "verify" the blades, do they all 4 fail?

There are professional companies that may be able to help, such as Drive Savers in California, but their service is not inexpensive.

See what the verify does. Its hard to imagine 4 out of 4 blades being bad. One issue with SSD's is they are very difficult to recover data from when they fail.

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Posted : 09/02/2021 2:30 am
(@ffuchs)
Active Member

hello,

I clicked on "validate", in this status the raid wasn't mounted on the desktop, so I saw the message "waiting for mounting", so I clicked on "mount", now I can see as status: validating, waiting for mount

does this mean, softraid is now validating the raid and only afterwards the raid will show up on the desktop?

in activity monitor I don't really see high process usage of softraid.

you mentioned cloning the device, do you meant to use a terminal tool like dd or ddrescue? do you have instructions for this?

at the moment "mountpoint" and disk identifier shows only a hyphen

many thanks,

 

ferdinand

 

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Topic starter Posted : 09/02/2021 1:49 pm
(@softraid-support)
Member Admin

No. Do "verify disk", a disk level verification.

 

This trick may be better than what I was going to recommend.

 

https://apple.stackexchange.com/questions/129030/how-to-identify-and-fix-files-with-corrupted-inaccessible-disk-blocks

 

Are you able to follow the terminal commands?

 

This would have been my suggestion:

dd bs=512 if=/path/to/damaged/file of=/Volumes/USB\ Disk/file bs=512 conv=noerror,sync

Or for a desktop file to a volume named "Recover":
dd bs=512 if=~/Desktop/mybadfile.avi of=/Volumes/recover/mybadfile.avi conv=noerror,sync

The last command means any unreadable area will be overwritten with zeros, but will keep the file intact in size.
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Posted : 09/02/2021 4:06 pm
(@ffuchs)
Active Member

hi,

many thanks for your suggestions, my problem ist, that the raid doesn't mount anymore, if I click on mount, it looks like that softraid tries to mount the raid but give up after 30 seconds.

please find attached a screenshot of the softraid-window.

Bildschirmfoto 2021 02 10 um 13.25.15

 

any chances to mount the filesystem again?

many thanks,

 

ferdinand

 

 

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Topic starter Posted : 10/02/2021 6:30 am
(@softraid-support)
Member Admin

@ffuchs

Attach a SoftRAID tech support file. Hopefully this is a problem with the driver not loading. the volume is not getting a mount point.

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Posted : 10/02/2021 12:48 pm
(@ffuchs)
Active Member

hi, please find attached the tech support file. many thanks for your help! cheers, ferdinand

 

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Topic starter Posted : 10/02/2021 12:54 pm
(@softraid-support)
Member Admin

@ffuchs

This is not good. There is no volume header information at all now.

When did this stop mounting?

Note in SoftRAID, there is no disk identifier? this means either the SoftRAID driver is not loaded (it is), or the volume header does not have the information need to publish the volume to macOS.

 

This is turning into a major issue as far as recovery goes.

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Posted : 10/02/2021 1:18 pm
(@ffuchs)
Active Member

last week I tried to copy everything to an external usb-drive, carbon copy cloner copied 3 of 5 TB. after that I made a normal shutdown of the macbook and this week I powered on the macbook again to see, if I can do something about the missing 2TB, but since starting the macbook the volume never showed up again. so nothing really happened since last week beside power off/power on.

regards, ferdinand

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Topic starter Posted : 10/02/2021 1:28 pm
(@softraid-support)
Member Admin

Did you save a SoftRAID Tech Support file before today? I don't see one, but it may help if you had.

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Posted : 10/02/2021 2:58 pm
(@ffuchs)
Active Member

yes, but it's a few weeks old (but nothing really happened since then), please find attached! cheers, ferdinand

 

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Topic starter Posted : 10/02/2021 6:19 pm
(@softraid-support)
Member Admin

Unfortunately your SoftRAID disks were not connected at the time you saved the report. So I cannot see the partition maps and look at the volume header. Was there another one, perchance?

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Posted : 10/02/2021 9:30 pm
(@ffuchs)
Active Member

hi, please find attached the last one that I found on my hard disk - but this support file could be from a different owc raid! do you have access to the support-tickets of owc? in a few hours I'm at the office, perhaps I have on a different computer more sr_supt files! cheers, ferdinand

 

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Topic starter Posted : 10/02/2021 11:37 pm
(@softraid-support)
Member Admin

If the volume name is SSD stripe, then this has the blades in it. good.

I am going to investigate whether we could paste the old volume header onto your disks. I am not sure it would work, but it may give some recovery options.

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Posted : 11/02/2021 12:56 am
(@ffuchs)
Active Member

yes, that's the name of the raid. many thanks for your efforts! cheers, ferdinand

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Topic starter Posted : 11/02/2021 1:05 am
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