Is it possible to convert a non partitioned drive to an MBR partition with out losing data? (Ubuntu 12.04)

Question

I tried gparted, but it doesn't like seeing an ext4 file system without the partition type being specified (I suspect). So it won't let me resize or anything since there is no partition. It is occurring to me that having a non partitioned drive with data on it is playing with fire. Worse yet, it is my /home mount point. Obviously I can do a full backup of my data and start from the ground up but I was hoping someone would have an idea of how I can do it without spending time on the backup/restore.

I realize this is a slim to none. Here's to hoping for someone more creative than myself providing a slim.

Here's a screenshot of the disk utility, showing what I mean by no partition:

Here is my fdisk -l output:

Disk /dev/sdb: 500.1 GB, 500107862016 bytes
255 heads, 63 sectors/track, 60801 cylinders, total 976773168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

Disk /dev/sdb doesn't contain a valid partition table

Answer 1

You cannot mount a drive for read/write that has no partitions on it. If the drive has no partitions on it, then it is simply raw and means basically nothing. Even in Windows, when you have one 'drive' - your C:\ drive is literally just a partition. You need a partition to utilize the drive, the partition needs to exist (and the MBR must know about it) if it is to be mounted, then a file system driver must exist in order to access it.

It sounds as though you have a drive with one partition, since you mentioned it has data on it. That is very different from an non-partitioned drive. There is nothing dangerous about having a non-partitioned drive, in my opinion, especially if it's a 'data only' drive.

If the drive in question only has 1 partition, and that 1 partition is the mount point of /home, then you can re-install Ubuntu on whatever drive you use for your root partition (/) and simply mount the drive you're speaking of as /home, just like you must be doing now.

You have a partition on that drive or you don't have data on that drive. I think your terminology is getting confused, I suggest you open a terminal in recovery mode and type:

sudo fdisk -l

I feel that will greatly benefit people trying to help you here.

PS: I have a feeling what you mean is you have one partition, the shared libs are corrupted, and your home directory is mounted on this partition as well. If this is the case, then you can simply copy your home partition off via:

sudo mkdir /mnt/old_home_folder
sudo mkdir /mnt/backup_drive
sudo mount -t ext4 /dev/sda1 /mnt/old_home_folder
sudo mount -t ext4 /dev/sdb1 /mnt/backup_drive
cp -r /mnt/old_home_folder/<username> /mnt/backup_drive

Where "username" is your username, sda1 is your HDD where your home directory exists, and sdb is some HDD you plugged in. This obviously varies a bit with setup so check what's going on with fdisk before doing anything.

Then you can re-install and copy it back to your new home directory.

Hope that helps you some, sorry I can't help more, it's a bit unclear what your setup is.