I am setting up an Open Media Vault, OMV, NAS box for my home storage requirements, detailed in the post Installing Open Media Vault. I don’t have the resources to setup a full RAID 5 array, this would require a box with space for 3 drives plus which I would actually need to purchase 3 drives.
So I am going with an older box with two 3GB drives in RAID 1 (mirrored). The idea is that if the box fails or I lose a drive the remaining drive can still be read. Not perfect for performance but I am going to use 7200 Barracuda Seagate drives, so hopefully that will help.
This article is about taking a drive from one from this RAID 1 and reading it on another box – worst case scenario.
Given that Open Media Vault run Debian the approach taken is to run a live USB version of Debian and mount the drive.
|1.||Create a Debian Live USB flash drive as described in article Create a Debian Live USB flash drive|
|2.||If you want to connect to this Debian Live instance using SSH follow the instructions int he post Enabling SSH access to Debian live USB|
|3.||Should you get timed out the password for the user “user” is “live”.|
|4.||At this point ensure the terminal window is not too small because the first screen you get will only:
If this happens to you just kill your terminal session, make the window bigger and try again. This time you should see:
|5.||Now install mdadm:
apt-get install mdadm rsync initramfs-tools
You will be asked If “the system’s root file system is located on an MD array (RAID…”
Ensure you enter “none” as your answer.
|6.||Now we want to see the drives that are available so run:
This should produce something like:
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 74.5G 0 disk └─md127 9:127 0 74.5G 0 raid1 sdb 8:16 1 7.5G 0 disk └─sdb1 8:17 1 1.2G 0 part /lib/live/mount/medium loop0 7:0 0 1.1G 1 loop /lib/live/mount/rootfs/filesystem.squashfs
|7||You can see from above that our remaining Mirror array disk is “sda”.
Create a temp directory to mount it in:
|8.||Now mount it using something like:
mount /dev/md127 /mirror
|9.||Because we enabled ssh login using root you can now sftp using WinSCP as root to move your files back to your laptop or PC.|
A useful command is:
mdadm --examine /dev/sd*
Which will give something like:
/dev/sda: Magic : a92b4efc Version : 1.2 Feature Map : 0x0 Array UUID : 99576b9e:6ffe87e8:fc43bf24:9c6b84ab Name : nas2:Mirror1 Creation Time : Sat Jun 4 05:42:20 2016 Raid Level : raid1 Raid Devices : 2 Avail Dev Size : 156181504 (74.47 GiB 79.96 GB) Array Size : 78085120 (74.47 GiB 79.96 GB) Used Dev Size : 156170240 (74.47 GiB 79.96 GB) Data Offset : 131072 sectors Super Offset : 8 sectors Unused Space : before=130992 sectors, after=11264 sectors State : clean Device UUID : 55c45427:8ba028de:ef53f68a:2cd44a10 Update Time : Wed Jun 22 21:26:19 2016 Checksum : 38926569 - correct Events : 122029 Device Role : Active device 1 Array State : .A ('A' == active, '.' == missing, 'R' == replacing) /dev/sdb: MBR Magic : aa55 Partition : 2573440 sectors at 64 (type 17) mdadm: No md superblock detected on /dev/sdb1.