Unable to mount LVM /root filesystem

[Vaibhav_Karve]

While installing Lubuntu, I chose the install with LVM option. After using it for many days, I wished to reduce the size of my /root from 900GB down to 300GB. I did this using the LVM GUI without using a Live CD! (I realize now that this was a serious mistake). LVM showed me that the /root filesystem did reduce to the desired size of 300G. However, on reboot I realized that the system is broken. Please show me a way to restore my /root partition, without having to completely clean and reinstall the filesystem.

Any help is much appreciated.

[vidtek]

While installing Lubuntu, I chose the install with LVM option. After using it for many days, I wished to reduce the size of my /root from 900GB down to 300GB. I did this using the LVM GUI without using a Live CD! (I realize now that this was a serious mistake). LVM showed me that the /root filesystem did reduce to the desired size of 300G. However, on reboot I realized that the system is broken. Please show me a way to restore my /root partition, without having to completely clean and reinstall the filesystem.

Any help is much appreciated.

VK-
You don't give much detail-try this from my earlier post.
http://ubuntuforums.org/showthread.php?t=2289087


Cheers, Tony.

[Vaibhav_Karve]

lubuntu@lubuntu:~$ blkid
/dev/loop0: TYPE="squashfs" 
/dev/sda1: UUID="9B74-C671" TYPE="vfat" 
/dev/sda2: UUID="cffe7e9c-89a4-47ce-8fff-553c40aaf87c" TYPE="ext2" 
/dev/sda3: UUID="CIufq8-wG3G-ft0M-VTVl-FbBw-3z6Y-aEntT9" TYPE="LVM2_member" 
/dev/mapper/lubuntu--vg-root: UUID="24422202-25c3-4903-a5e4-016de8b72907" TYPE="ext4" 
/dev/mapper/lubuntu--vg-swap_1: UUID="ca5d823c-211d-4ccf-9901-45ae5acb87b2" TYPE="swap" 
/dev/sdb1: LABEL="VAIBHAV PEN" UUID="2297-70B3" TYPE="vfat" 
/dev/zram0: UUID="4f914913-8447-4739-b988-57d9b5b173aa" TYPE="swap" 
/dev/zram1: UUID="fdc55086-34ac-4999-8a18-0288a23c165f" TYPE="swap" 
/dev/zram2: UUID="98682606-a64f-4494-a412-3a3911b3a80e" TYPE="swap" 
/dev/zram3: UUID="a3124d4f-fd7c-4f88-86a2-799d97a02b3c" TYPE="swap"

lubuntu@lubuntu:~$ mount /dev/mapper/lubuntu--vg-root /mnt
mount: only root can do that
lubuntu@lubuntu:~$ sudo mount /dev/mapper/lubuntu--vg-root /mnt
mount: wrong fs type, bad option, bad superblock on /dev/mapper/lubuntu--vg-root,
       missing codepage or helper program, or other error
       In some cases useful info is found in syslog - try
       dmesg | tail  or so

Tony, here's the output.

[vidtek]

lubuntu@lubuntu:~$ blkid
/dev/loop0: TYPE="squashfs" 
/dev/sda1: UUID="9B74-C671" TYPE="vfat" 
/dev/sda2: UUID="cffe7e9c-89a4-47ce-8fff-553c40aaf87c" TYPE="ext2" 
/dev/sda3: UUID="CIufq8-wG3G-ft0M-VTVl-FbBw-3z6Y-aEntT9" TYPE="LVM2_member" 
/dev/mapper/lubuntu--vg-root: UUID="24422202-25c3-4903-a5e4-016de8b72907" TYPE="ext4" 
/dev/mapper/lubuntu--vg-swap_1: UUID="ca5d823c-211d-4ccf-9901-45ae5acb87b2" TYPE="swap" 
/dev/sdb1: LABEL="VAIBHAV PEN" UUID="2297-70B3" TYPE="vfat" 
/dev/zram0: UUID="4f914913-8447-4739-b988-57d9b5b173aa" TYPE="swap" 
/dev/zram1: UUID="fdc55086-34ac-4999-8a18-0288a23c165f" TYPE="swap" 
/dev/zram2: UUID="98682606-a64f-4494-a412-3a3911b3a80e" TYPE="swap" 
/dev/zram3: UUID="a3124d4f-fd7c-4f88-86a2-799d97a02b3c" TYPE="swap"

lubuntu@lubuntu:~$ mount /dev/mapper/lubuntu--vg-root /mnt
mount: only root can do that
lubuntu@lubuntu:~$ sudo mount /dev/mapper/lubuntu--vg-root /mnt
mount: wrong fs type, bad option, bad superblock on /dev/mapper/lubuntu--vg-root,
       missing codepage or helper program, or other error
       In some cases useful info is found in syslog - try
       dmesg | tail  or so

Tony, here's the output.

I don't understand your /dev path, it doesn't make any sense.

your command should be more like :

sudo mount /dev/sd?? /mnt

what is this /dev/mapper/lubuntu--vg-root ??

Tony

[Vaibhav_Karve]

what is this /dev/mapper/lubuntu--vg-root ??

Tony

That is the default name that LVM chose for my /root. I did not change that name. The root and swap are a part of /dev/sda3.

[vidtek]

That is the default name that LVM chose for my /root. I did not change that name. The root and swap are a part of /dev/sda3.

VK-

Can't say I'm sure about LVM's but to sort your problem you would probably need to go to the actual hdd which as you say is sda3.

you could try mounting that (and probably really stuff it up).

LVM's are a real pain-I learned early on they're more trouble than they're worth, especially now storage is so cheap.

Tony.

[Vaibhav_Karve]

VK-

Can't say I'm sure about LVM's but to sort your problem you would probably need to go to the actual hdd which as you say is sda3.

you could try mounting that (and probably really stuff it up).

Here's the output for that --

lubuntu@lubuntu:~$ sudo mount /dev/sda3 /mnt
mount: unknown filesystem type 'LVM2_member'

LVM's are a real pain-I learned early on they're more trouble than they're worth, especially now storage is so cheap.

Tony.

Thanks Tony. But be that as it may, right now I have little option but to try and restore my system on LVMs.

[vidtek]

Here's the output for that --

lubuntu@lubuntu:~$ sudo mount /dev/sda3 /mnt
mount: unknown filesystem type 'LVM2_member'

Thanks Tony. But be that as it may, right now I have little option but to try and restore my system on LVMs.

VK-

Another tutorial on chroot that is supposed to work for LVM's

https://help.ubuntu.com/community/Gr...ing#via_ChRoot

Cheers Tony.

[sandyd]

Can you post the output of

lvdisplay
vgdisplay
ls -l /dev/mapper/

Commands may require sudo.

If you did not do the correct procedure to resize the root partition, or miscalculated, the LVM will have chopped off part of your root partition
Partitions in a LV have to be resized before resizing LV (Logical Volume), otherwise partition will be cut off
If calculations are incorrect and you shrink more than you should have, you will chop off part of the root partition as well.
Its entirely possible that your data is still there if you haven't done anything else other than resizing that one LV. In this case, we can just try to re-extend the LV to see if the data reappears. Since it is standard in Ubuntu LVM setups to have no free space, we can just extend LV to maximum size.

Should be just

sudo lvextend -l +100%FREE /dev/mapper/lubuntu--vg-root
sudo e2fsck -f /dev/mapper/lubuntu--vg-root

but we should probably check the output of the commands above to see if there are any issues before we begin extending.

Then, to resize again after FS is confirmed working:

sudo lvreduce -r -L 300G /dev/mapper/lubuntu--vg-root