Extend LVM and revert to original setup


New Member
Mar 28, 2021
Dear All
Today I had some time to study and test LVM on my home server.
I did some changes, but now I cannot revert the server to original setup.
These are the tasks I did:
- I physically added a 250 Gb Sata SSD on /dev/sda device. It was from my RP4 old server, and, to blank it all, I dd'ed it with some /dev/zero
- I created a 8e partition (LVM) on /dev/sda1
- pvcreate /dev/sda1
- vgextend pve /dev/sda1
- lvextend /dev/mapper/pve-data -L +148G

At this point everything seemed to work fine.
I could see updated free space from proxmox GUI. Nice! Good job!

BUT... When I tried
fsck -nv /dev/mapper/pve-data
I got this error:
fsck from util-linux 2.33.1
e2fsck 1.44.5 (15-Dec-2018)
ext2fs_open2: Bad magic number in super-block
fsck.ext2: Superblock invalid, trying backup blocks...
fsck.ext2: Bad magic number in super-block while trying to open /dev/mapper/pve-data

The superblock could not be read or does not describe a valid ext2/ext3/ext4
filesystem. If the device is valid and it really contains an ext2/ext3/ext4
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>
e2fsck -b 32768 <device>

So I realized it was time to go back.

The problem is that LVM-thin cannot be reduced or resized.
SO I cannot "pvmove /dev/sda1" because "No extents available for allocation.".
AND I cannot "lvresize /dev/mapper/pve-data -L -148G" because "Thin pool volumes pve/data_tdata cannot be reduced in size yet.". Same result with "lvreduce".
AND even "vgreduce pve /dev/sda1" cannot executed because "Physical volume "/dev/sda1" still in use".

So... the point of no return?

My questions are:
1. is the fsck a real error, or can I go on with this "warning", safe in my life?
2. How can I remove /dev/sda1 from LVM ?

I would prefer not to wipe the main storage device and re-install proxmox from scratch... I like my virtual machines and lxc... really don't want to start again all the stuff...

thanks a lot in advance


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