Visit Jeremy's Blog.
Go Back > Forums > Linux Forums > Linux - Hardware
User Name
Linux - Hardware This forum is for Hardware issues.
Having trouble installing a piece of hardware? Want to know if that peripheral is compatible with Linux?


  Search this Thread
Old 03-29-2010, 07:53 AM   #1
LQ Newbie
Registered: Sep 2006
Location: Canberra, Australia
Distribution: Ubuntu
Posts: 7

Rep: Reputation: 1
Question Access data on nvraid stripe set using dmraid and loop devices?

I am in one of those terrible situations... 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. 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). 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.

dmraid seems to be ignoring my loop devices . 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?

Old 04-01-2010, 10:49 PM   #2
LQ Newbie
Registered: Sep 2006
Location: Canberra, Australia
Distribution: Ubuntu
Posts: 7

Original Poster
Rep: Reputation: 1
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.
1 members found this post helpful.
Old 12-15-2012, 03:12 PM   #3
LQ Newbie
Registered: Dec 2012
Posts: 2

Rep: Reputation: Disabled
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?


data, device, dmraid, loop, recovery

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
dmraid + ICH10R RAID10: “RAID set was not activated” TheCyberShadow Linux - Hardware 1 01-30-2010 02:46 PM
DMRAID - attempt to access beyond end of device Quakeboy02 Linux - Kernel 3 03-05-2007 01:22 PM
need help with DMraid&NVraid dualboot strange|ife Linux - Newbie 1 01-04-2007 11:13 PM
Can't get more than 8 loop devices going tommyrot Linux - Newbie 4 07-27-2006 10:17 PM
raid-0 XFS stripe size and stripe width ganja_guru Linux - Software 1 09-04-2005 08:15 AM > Forums > Linux Forums > Linux - Hardware

All times are GMT -5. The time now is 04:07 AM.

Main Menu
Write for LQ is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
Facebook: linuxquestions Google+: linuxquestions
Open Source Consulting | Domain Registration