Re: [Bug-ddrescue] List or Forum for ddrescue

[Florian Sedivy]

Hello John!

There certainly is a lot of additional information about rescuing RAIDs out there, but I will try to share my own experience here. 

I assume you are on a Mac working in OS X and created two image files of the two member disks. To avoid data loss you are working on copies of these images or you are protecting the originals from being written to in some other way (uchg, shadow image, etc.). Now you cannot use Disk Utility or diskutil to recreate the Software-RAID, because the former will not accept images, and both of them will reformat the disks.  

But you can use software like Data Rescue for Mac, that allows you to add your images, select them both, and treat them as a striped RAID-Set. You can then scavenge for files or even try to mount the volume, while Data Rescue will write-protect the images. Or you can "clone" the RAID-volume, effectively creating a regular image to perform other recovery operations on. 

In your case Data Rescue should automatically detect the order and stripe-size of the RAID. I once had disks from an NTFS-RAID0, where every software I tried could not detect the correct RAID configuration. I eventually had to recreate one specific JPEG from its two corrupted halves manually in a hex-editor do reconstruct the correct values (one of the drives had an offset of 10 sectors). To test the configuration of the RAID-Set scavenge it for pictures and see if they look ok. If they look "striped", you have to modify order, stripe size or offset. 

If somebody knows a way to merge two files in a striped manner using the shell, I would like to hear about that. I couldn't find a tool for that. 

Greetings, 
Florian

Am 31.10.2013 um 06:49 schrieb John:

Hi Antonio,

I have some questions regarding what approach to follow to reassemble the barrels of a stripe. Is there a general list or Forum which would be better suited to my question?

The two drives appear to be intact but the stripe was broken due to power loss. The stripe was created using Apple's Disk Utility so it was a software raid0. I figured if I could copy the date off of the drives I might be able to attempt to reassemble the barrels back into an intact disk. I am not sure how I might do that at this point but some research reveals some possible techniques to try.

Regards,

J.

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