Rescuing data off RAID disks

Forum rules
Before you post please read this
xjas
Level 1
Level 1
Posts: 22
Joined: Mon Nov 05, 2012 8:47 pm

Rescuing data off RAID disks

Postby xjas » Thu Aug 18, 2016 3:17 pm

I had a little 2-bay Raidon NAS (SL3650-LB2) running for a while with 2x2TB in RAID1. Unfortunately it seems to have died (power supply problems.) I'm fed up with messing with it so I'm going to replace it with a 4-drive FreeNAS setup like I should have built in the first place. :P

Anyway obviously I'd like to rescue the data. The Raidon box ran embedded Linux (not sure what version) and formatted its drives in XFS. Can I plug the drives into a standard desktop PC and have it recognize the RAID volume without screwing up the file system? Or can I plug just *one* drive in and will it show up as a single volume?

Any help is appreciated - kind of paranoid while messing with my backup storage. Thanks.

DeMus
Level 6
Level 6
Posts: 1029
Joined: Sat Aug 15, 2009 5:11 pm

Re: Rescuing data off RAID disks

Postby DeMus » Thu Aug 18, 2016 3:27 pm

xjas wrote:I had a little 2-bay Raidon NAS (SL3650-LB2) running for a while with 2x2TB in RAID1. Unfortunately it seems to have died (power supply problems.) I'm fed up with messing with it so I'm going to replace it with a 4-drive FreeNAS setup like I should have built in the first place. :P

Anyway obviously I'd like to rescue the data. The Raidon box ran embedded Linux (not sure what version) and formatted its drives in XFS. Can I plug the drives into a standard desktop PC and have it recognize the RAID volume without screwing up the file system? Or can I plug just *one* drive in and will it show up as a single volume?

Any help is appreciated - kind of paranoid while messing with my backup storage. Thanks.


Don't apologize, you should be paranoid when messing with your backup. I think, but mind you it is a guess, that you can use one disk of the RAID and connect it and be able to read it since you used RAID 1: mirror. You have the same, complete, info on both disks.
I would however be wrong so just google the problem and you will find many answers. http://superuser.com/questions/83923/can-a-mirrored-raid-1-disk-be-plugged-into-another-system-to-be-read Here they say that if you have RAID 1 made with software raid (mdadm) then yes. When it is a hardware RAID made using a RAID controller then no since there is data on the disk referring to the controller.
Just read, ask around before you do something cause you never know what will happen.
Last edited by DeMus on Fri Aug 19, 2016 12:21 am, edited 1 time in total.

Laurent85
Level 13
Level 13
Posts: 4849
Joined: Tue May 26, 2015 10:11 am

Re: Rescuing data off RAID disks

Postby Laurent85 » Thu Aug 18, 2016 5:09 pm

Connect both drives to your computer, from Mint open a terminal to install mdadm:

Code: Select all

apt install mdadm

Then post back the command results:

Code: Select all

sudo lsblk -o name,size,fstype,uuid,parttype,label,mountpoint
sudo mdadm --examine --scan
Image

kwisher
Level 5
Level 5
Posts: 781
Joined: Wed Mar 05, 2008 12:54 pm
Location: Greentown, Indiana USA

Re: Rescuing data off RAID disks

Postby kwisher » Sat Aug 20, 2016 12:56 pm

I would suggest getting the new NAS setup and running first before doing ANYTHING with the 2 existing disks. Were you planning on using the existing disks in the new NAS or 4 new disks? I would highly suggest cloning the existing disks before any attempts at data rescue just in case something go awry.
The instructions suggested Windows XP or better, so I installed Linux :)

Petermint
Level 4
Level 4
Posts: 309
Joined: Tue Feb 16, 2016 3:12 am

Re: Rescuing data off RAID disks

Postby Petermint » Sun Oct 02, 2016 5:10 am

What happened? Were your disks using LVM or anything?

I ask because I tried to recover files from one disk of a Linux software RAID 1 array and could not access anything. I did not have a record of the configuration used to create the array. One disk died. Every attempt to recreate the array failed. Every attempt to recover files from the remaining disk failed.

I used to easily recover files from either disk created by the software RAID 1 supplied in XP server. Both disks were identical and usable outside of the array. In fact I often used that as a simple way to replicate system disks.

My attempts at Linux software RAID 1 have used a few options and in every case a recovery from a single disk has failed. Now I backup to a single disk and let rsync create the second disk.

I would like to see how you use lsblk and mdadm to recreate the array from a single disk.

xjas
Level 1
Level 1
Posts: 22
Joined: Mon Nov 05, 2012 8:47 pm

Re: Rescuing data off RAID disks

Postby xjas » Sat Jul 15, 2017 2:58 am

Petermint wrote:What happened? Were your disks using LVM or anything?

I ask because I tried to recover files from one disk of a Linux software RAID 1 array and could not access anything. I did not have a record of the configuration used to create the array. One disk died. Every attempt to recreate the array failed. Every attempt to recover files from the remaining disk failed.

I used to easily recover files from either disk created by the software RAID 1 supplied in XP server. Both disks were identical and usable outside of the array. In fact I often used that as a simple way to replicate system disks.

My attempts at Linux software RAID 1 have used a few options and in every case a recovery from a single disk has failed. Now I backup to a single disk and let rsync create the second disk.

I would like to see how you use lsblk and mdadm to recreate the array from a single disk.


Man, sorry I forgot to reply to this, but in case it's still relevant months later:

I ended up plugging in both drives into an external SATA bay and they showed up as a RAID array using XFS, so I was able to get all the data off them without any drama. (The machine I mounted them on already has a RAID1 volume running so mdadm etc. was already set up.) I don't know if they were using LVM; I've still got both disks as they were so I can look further into how they were configured when I have some time.


Return to “Mounting Partitions”