Not enough components to start the RAID array?
I'm trying to retrieve data from a "Western Digital MyBook World Edition (white light)" NAS device. This is basically an embedded Linux box with a 1TB HDD in it formatted in ext3. It stopped booting one day for no apparent reason.
I have extracted the HDD from the NAS device and installed it in a desktop machine running Ubuntu 10.10 in the hope of accessing the files on the drive. Unfortunately, Ubuntu has not been able to mount the drive automatically.
Having started up Disk Utility I see the drive as a multi disk device called "Array (Array)" showing Metadata Version 0.90.0. The device state is: "Not Running, not enough components to start". When I click the "Start RAID Array" button I get an error saying: "Not enough components to start the RAID array".
Can you please tell me which components are missing and how to install them to get access to the drive's filesystem?
WD MyBooks use mdadm. It's a SoftRAID toolkit. I don't know why they use it in single-drive setups but there you go.
I'm guessing some bits here. I don't have one but I just want you to know: what I suggest may destroy your data. I really hope it doesn't but don't take any warranty from this post. I'm sure you have a backup ;)
sudo apt-get install mdadm
That will install mdadm (obviously) but it'll also ask to install postfix (if that isn't installed anyway). Just set it up with the default options.
Now you might be able to open up Disk Utility (palimpsest) and click Run Array. You might not.
If you can't, note the partition number for that drive (something like /dev/sdg1) and lets continue manually:
sudo mdadm --assemble --scan
# might work - it'll add a /dev/mdX device if it does
sudo mdadm --assemble --run /dev/md0 /dev/sdg1
# obviously sub in the right partition numbering
Assuming that goes well, you just need to mount the array now. You should be able to do this from nautilus' sidebar, or palimpsest, or manually:
sudo mkdir /media/raiddisk
sudo chmod 777 /media/raiddisk
sudo mount /dev/md0 /media/raiddisk