[SOLVED] Partition problems

[wgg]

When I start GParted I get the following error:


The kernel is unable to re-read the partitiontables on the following devices:
- /dev/mapper/minotaur-root

When checking the info of this partition I get the following warning:


e2label: No such file or directory while trying to open /dev/mapper/minotaur-rootp1
Couldn't find valid filesystem superblock.

I'm not having any problems accessing files on this drive, but this message worries me. I haven't made any changes to my partitions for well over a year, but I did recently have a power outage that forced my computer to reboot unexpectedly.

Does anyone know what my problem might be?

[Pro-reason]

Perhaps you should boot from the live CD and run fsck on all your drives.

[wgg]

Thanks for your help, Pro-reason. I tried that and got the following:


ubuntu@ubuntu:~$ sudo fsck /dev/sda
fsck 1.40.8 (13-Mar-2008)
e2fsck 1.40.8 (13-Mar-2008)
fsck.ext2: Superblock invalid, trying backup blocks...
fsck.ext2: Bad magic number in super-block while trying to open /dev/sda

The superblock could not be read or does not describe a correct ext2
filesystem. If the device is valid and it really contains an ext2
filesystem (and not swap or ufs or something else), then the superblock
is corrupt, and you might try running e2fsck with an alternate superblock:
e2fsck -b 8193 <device>


I also tried fsck on the numbered (partitions?) under sda:


ubuntu@ubuntu:~$ sudo fsck /dev/sda1
fsck 1.40.8 (13-Mar-2008)
e2fsck 1.40.8 (13-Mar-2008)
/dev/sda1: clean, 42/62248 files, 49457/248976 blocks

ubuntu@ubuntu:~$ sudo fsck /dev/sda2
fsck 1.40.8 (13-Mar-2008)
e2fsck 1.40.8 (13-Mar-2008)
fsck.ext2: Attempt to read block from filesystem resulted in short read while trying to open /dev/sda2
Could this be a zero-length partition?

ubuntu@ubuntu:~$ sudo fsck /dev/sda5
fsck 1.40.8 (13-Mar-2008)
fsck: fsck.lvm2pv: not found
fsck: Error 2 while executing fsck.lvm2pv for /dev/sda5


What I don't understand about all this is if there is something wrong with the drive/partitions, why am I able to use it without any problems?

[Pro-reason]

Do this to get info about your drives:



sudo fdisk -l
sudo blkid

[wgg]

Here's what I got from fdisk -l:


Disk /dev/sda: 320.0 GB, 320072933376 bytes
255 heads, 63 sectors/track, 38913 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x000f34ab

Device Boot Start End Blocks Id System
/dev/sda1 1 31 248976 83 Linux
/dev/sda2 32 38913 312319665 5 Extended
/dev/sda5 * 32 38913 312319633+ 83 Linux

Disk /dev/sdb: 320.0 GB, 320072933376 bytes
255 heads, 63 sectors/track, 38913 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x3767544a

Device Boot Start End Blocks Id System
/dev/sdb1 1 38913 312568641 83 Linux


And from blkid:


/dev/mapper/minotaur-swap_1: TYPE="swap" UUID="91cf150c-8253-4235-a904-95e1856b57c4"
/dev/mapper/minotaur-root: UUID="76fd42f8-0655-41bb-9abf-30d21f742493" SEC_TYPE="ext2" TYPE="ext3"
/dev/sda1: UUID="a92b6336-8987-4873-9984-b7b590f49f45" SEC_TYPE="ext2" TYPE="ext3"
/dev/sda5: UUID="65cDYg-vxJf-qHYd-9V3U-8UzM-2Gtt-uGJEoI" TYPE="lvm2pv"
/dev/sdb1: UUID="5dd70fc7-386c-4f69-91f0-c49cf42c5234" TYPE="ext3"

[easoukenka]

I have had 2 brand new usb drives and I have always gotten bad superblock messages along with other erros. Drives on 2 year warranty so I will just see what happens I guess.

I have a post at http://ubuntuforums.org/showthread.php?t=964625 no replies yet though

I have run all the scans on it but no luck. I did backup my partition table just in case.

[wgg]

Can anyone help?

[Pro-reason]

Here's what I got from fdisk -l:



And from blkid:

There is something very strange about your /dev/sda5. It is marked as having a “lvm2pv” file system, instead of the more usual “ext3”. I have never heard of this, and can't find anything on-line. This is very weird. Do you know anything about it?

I would back up my files and re-install.

[wgg]

Ahah, that rings a bell. Back when I first installed Ubuntu (feisty fawn, I think) I had the option to partition my drive using Logic Volume Manager (LVM2). I didn't understand enough about partitioning (and still don't) so I just choose all the default and/or recommended options.

So, having looked around a bit I've discovered that physical partitioning tools such as gparted, parted, fdisk, etc, can't handle virtual partitions such as the ones created by LVM.

To manage these partitions you need to use LVM tools, such as lvm (command line) or system-config-lvm (graphical user interface). For anyone wondering these tools can be installed using apt-get or the Synaptic Package Manager.

Voila, problem solved.