Access data on nvraid stripe set using dmraid and loop devices?
 

Hi,
I am in one of those terrible situations... :redface: My motherboard died and I am left with a nvidia nforce raid stripe set that I need to get data off. I guess I should have setup that backup regime. :o Some search results have suggested that dmraid may be my white knight.

I have pulled the data off each of the disks (3 of them) into image files (using ddrescue) and created loop devices (/dev/loop[1-3], using losetup). :D I am running 32bit ubuntu 9.10 btw.

When I do a "dmraid -ay" it tells me it found a raid set but has not activated it. When I do a "dmraid -r" it tells me I have a raid5 array on one of my /dev/sd? devices. :cry:

dmraid seems to be ignoring my loop devices :scratch:. Does anyone know if dmraid actually works with loop devices? If it does is there a way for me to point it directly at the devices and get it to do its auto-magic?

Is there a simpler/better way of doing this?


Thanks

Hi,
No one seems to know anything about dmraid and loop devices. I posted on this forum, Ubuntu's forum and Nvidia's forum. Finally I tried to subscribe to the redhat's mailing list for dmraid and never got a response - I suppose the list is dead.

In desperation I pulled apart one of my other PC's and physically connected the nvraid stripe set to the motherboard. I created an X-Ubuntu 9.10 live-USB stick and booted up with my fingers crossed. The system started and dmraid auto-detected the stripe array. For those who may be interested:
- use the sudo dmraid -ay to force auto-detection of arrays and activate them
- use the sudo dmraid -r command to get details on the arrays
- you can also use gparted to see the raid devices and their respective partitions; just like any other drive
- I created a directory to use as a mount point for my partition
- look in /dev/mapper for the names of your partitions
- I used sudo mount -t nfts -o users,owner,ro,umask=000 dev/mapper/<partiton name> <mount dir> to mount the partition

This successfully mounted by stripe set partition. Then I tar'd the contents to a USB drive using sudo tar -zcvf /media/<USB drive>/files.tar.gz <mount dir> To get the files out of the tar archives I use tar -zxvf /media/<USB drive>/files.tar.gz and the files extract into the directory you are running the tar command from.

I wish I could have found an answer for using loop devices; but, alas, it was not to be. It certainly would be a huge improvement if dmraid were updated to support loop devices.

dmraid and loop, another open case
 

I recently had a similar problem: one out of my two dmraid (NVidia) RAID-0 disks broke its mechanics.
I can manage (not easily) to dump the contents of both the hard-disks but I don't know whether I will be able to merge data together as I would have done (with loop devices) in case of RAID created by mean of mdadm.

No news even after two years from your last post?