[SOLVED] mounting a partition in raid 0 array

Cyrolancer · 12-15-2012, 12:25 PM

Hello,

I am having a real problem. It suddenly occured and I couldn't do anything to recover.

The problem is, I have a Sony laptop with 60 GB 1.8 inch RAID 0 configured disks. I think one of the disks was failed and somehow Windows restarted. Now, Windows only boots in the recovery partition, not the main one.

The thing is, I have managed to retrieve backups of the disks using ddrescue. I have also managed to mount them into my main Ubuntu machine as loop0 and loop1. I searched the internet about what I can do to rebuild raid array using these loopback devices. I found mdadm.

What can I do further?

Edit: I have found the solution, the commands I have written were incorrect. I have read the man pages deeply again and again and then found the correct parameters.

Snark1994 · 12-15-2012, 04:57 PM

Well done for solving the problem - could you post the exact (correct) commands you used? This way future users with the same problem can benefit from your solution.

Thanks,

Cyrolancer · 12-15-2012, 05:24 PM

First, I used the exact commands in the related Ubuntu Wiki: https://help.ubuntu.com/community/DataRecovery . I installed gddrescue and followed the instructions.

After that, I have used the commands in a post of Anandtech forums: http://forums.anandtech.com/showpost...02&postcount=7

However, mdadm command didn't work in my case. I got the "superblock problem". Then, I used

Code:

mdadm --build --level=0 --raid-devices=2 --chunk=64 /dev/md0 /dev/loop0 /dev/loop1

I have RAID0 (level=0) and 2 hard drives -therefore 2 hdd images- (raid-devices=2). You need to specify the chunk size (chunk=64), or you cannot mount the partitions under RAID0. I have used the RAID BIOS to determine chunk size (it was written on the screen when I entered the RAID utility, using CTRL+I).

/dev/md0 is the block device defines the RAID array. You must use an unused md device to build the RAID array.
/dev/loop0 is the image of the first hdd
/dev/loop1 is the image of the second hdd

In your case, you may destroy your image or your RAID array completely but I was desperate and I needed to do something to rescue only 1 file, then acted bravely. I also took backups of the image files to some other storage media, because taking the images from the broken disks lasted 5 hours.

Also, you can use dmraid but I couldn't manage to define the loopback devices as an input to dmraid. Automatic find didn't work in my case.

It is a bit complex and as I said you may destroy your data. Please do not take this explanation as the ultimate solution, try the solutions on Ubuntu Wiki and Anandtech forums at first, then look at the man pages of mdadm and try the above solution as your final move.

The info about the mdadm package I used:

Code:

# aptitude show mdadm
Package: mdadm                           
State: installed
Automatically installed: no
Version: 3.2.5-1ubuntu3

Note: I have Googled a lot, tried a lot and found that the info described in the links are much more better than the others. I didn't want to credit everything to me and I gave the links. If this is against the rules, I am sorry.

Snark1994 · 12-16-2012, 03:04 AM

Quote:

Originally Posted by Cyrolancer

I have Googled a lot, tried a lot and found that the info described in the links are much more better than the others. I didn't want to credit everything to me and I gave the links. If this is against the rules, I am sorry.

Ahaha! The rules on this forum are generally rather sensible, you can find them here. I'm not sure exactly what rule you thought you might be breaking... It's true people can get a little annoyed if the only content in your post is a link to LMGTFTY or similar, but posting the links where you got the information from is definitely a good idea: that way people can read more on the topic if they're interested, and see where you got the information from.

Thanks again,