Question: I have Windows 7 Pro installed in my system. Now i want to dual boot my computer with Ubuntu 12.0. How can I install Ubuntu alongside Windows 7?

For that, I think I need one more primary partition but when I run the ubuntu installation disk, I don't know where I need to install it. The disk names in ubuntu are confusing.

If I can install with wubi, how do I do? It has only two options and does not have any option to install ubuntu alongside windows.

Answer: 
The folks at this location actually mapped the serial numbers of the physical disks to separate names to help identify those in the RAID array. They used UDEV rules for it. This eliminates the guesswork since serial numbers are typically written on the disk paper labels.

In the below link you'll find real 2 drive failure on a RAID6 setup (+) and recovery. Take a look. You might be able to identify in a similar way which drive you need to unplug.

Regards,

[RAID 6 + XFS + MDADM](http://www.microdevsys.com/WordPress/2012/04/02/linux-htpc-home-backup-mdadm-raid6-lvm-xfs-cifs-and-nfs/3/)

[RAID 6 UDEV Naming](http://www.microdevsys.com/WordPress/2012/04/01/linux-persistent-naming-of-sata-devices-through-udev-rules/)
Assuming you disk setup is as follows:
![Disk layout constructed from the comments](https://i.stack.imgur.com/ap6cJ.png)

With:  

sda1 and sdb1 as md1 (mirrored) root  

sda2 and sdb2 as md0 (striped) boot  

sda3, sdb3, sdc1, sdd1 and sde1 as md2 (RAID5) /home

Since you lost drive 2 (sdb) you:

* You lost md0. A stripe needs \*\*all\* of its drives. You will need to restore this from backup or reinstall it.
* You lost one drive from md1. Since that is a mirror it will still work. (without redundancy atm)
* You lost on drive from md2. Since that is a RAID5 is will work with one drive lost. You should still be able to access all your data.

My first step would be to check my backups. Nothing should go wrong while you fix your RAID arrays. But it is better to be safe and have backups. Since both / and /home are still readable in degraded mode I suggest to start with that.

Afterward pull the broken drive (disk 2, aka sdb), replace it with a new drive and partition the drive. I understood from your comments that it used the same setup as the first drive. Which means that you can configure it correctly from your notes, or 'spy' at sda.

Next fix the three broken RAID arrays.

md0 is lost. You will need to recreate it and restore from backup.

md1 might work with `mdadm --assemble /dev/md1 /dev/sda1 /dev/sdb1`

md2 might work with `mdadm --assemble /dev/md2 /dev/sda3 /dev/sdb3 /dev/sdc1 /dev/sdd1 /dev/sde1`

**Might**. I am a BSD guy (not a Linux user) which uses hardware RAID cards. Please double check everything before committing to these commands. This includes your checking your backups.