ubuntu 12.04 - How do I recover data from only a single drive in RAID 1 setup on Synology DS214+ NAS?

I'm doing this so I know how to recover my data in case the NAS itself dies out and I'm only left with just a single drive from the 2nd bay (or from the 1st bay).

Setup

• Synology DS214+ NAS


• 2x 4TB drives in Raid 1 (non-SHR)


• Created one volume and a few shared folders

What I want to achieve

Recover the data from the drive I removed from the 2nd bay without using the other drive in the 1st bay by using Ubuntu 12 running in VMware Player.

Things I have done so far

1. shutdown NAS


2. removed the drive from the 2nd bay of my NAS


3. setup ubuntu 12.04 on vmware player


4. installed lvm2 and mdadm


5. inserted my drive from the 2nd bay (which I want to recover the data from) to a USB enclosure which is inserted to my laptop

Here's what the drive looks in "Disk Utility"

I've been trying to follow this FAQ from Synology but no luck.

I tried running few commands and here's what I got:

root@ubuntu:~# mdadm -Asf && vgchange -ay
mdadm: No arrays found in config file or automatically
root@ubuntu:~# mdadm --examine /dev/sdb
/dev/sdb:
   MBR Magic : aa55
Partition[0] :   4294967295 sectors at            1 (type ee)
root@ubuntu:~# mdadm --examine /dev/sdb1
mdadm: No md superblock detected on /dev/sdb1.
root@ubuntu:~# mdadm --examine /dev/sdb2
mdadm: No md superblock detected on /dev/sdb2.
root@ubuntu:~# mdadm --assemble /dev/md0 /dev/sdb1
mdadm: no recogniseable superblock on /dev/sdb1
mdadm: /dev/sdb1 has no superblock - assembly aborted
root@ubuntu:~# mdadm --assemble /dev/md0 /dev/sdb2
mdadm: no recogniseable superblock on /dev/sdb2
mdadm: /dev/sdb2 has no superblock - assembly aborted
root@ubuntu:~# mdadm --assemble /dev/md0 /dev/sdb
mdadm: Cannot assemble mbr metadata on /dev/sdb
mdadm: /dev/sdb has no superblock - assembly aborted
root@ubuntu:~# cat /proc/mdstat
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
unused devices: 
root@ubuntu:~#

I do not understand why the Disk Utility is showing up 2.6GB, 2.1GB, and 1.8TB. It doesn't sum up to 4TB.

Answer

I found out that my USB enclosure doesn't support 4TB. I tried to have it detected by Windows OS but it only reported to have 1.64TB. So I bought SATA to USB kit that supports 4TB and then I was able to start the raid. Here's what it's supposed to look like: