Manually mount/unmount LVM from USB --now only one logical volume

xtian · 2017-10-15 22:35:16

Using the Archlinux USB install media, I've completed the install of Arch except for a problem with grub.
The last thing I did was:

- reinstall grub to the device `sda` (instead of the boot partition `sda1`)
- remake the grub config,
- unmount everything (swap, var, home, etc. but root was busy),
- rebooted anyway (>_<)

Before, the system would not boot to grub, but I was able to unencrypt the partition, and `arch-chroot` into the new system from the USB installer.

    + -- sda  (windows)
    + -- sdb  (arch)
    |-- sdb1  /boot
    |--+ sdb2   
       |--+ Luks
          |- swap    /LVM-swap
          |- root    /LVM-root
          |- var     /LVM-var
          |- home    /LVM-home

After reboot into the new system, the system launched grub, asked for disk passphrase, and defaulted to grub CLI.

Trying to fix this I booted from installer USB, and unlocked the Luks/LVM. However, when I list the logical volumes (`# lvs`), I only get `/LVM-root`--`/swap`, and `/home`, `/var` are gone.

Searching for solutions its easier to find posts with existing systems, and not booting from USB during install.

- No LVM Backup yet. Looking into `/etc/lvm` on the USB and mounted logical volume I find backup and archive files, and both only list the root partition.

- I have UUIDs from setting up persistent volume naming (`mkinitcpio.conf`), but no partition data.

- I found a command `pvck` to restore without volume backups (Recover LVM Volume Groups and Logical Volumes WITHOUT Backups), but this reports "could not find LVM label on `/dev/sda2`.

What sort of LVM error is this?

- There are no error messages.
- VGdisplay shows the volume group.
- LVS shows just the root
- arch-chroot works--whatever that means (without var, home)
- No additional errors. Poof!

What sort of LVM error presents like this?
Do I need to reinstall? Would it be easier to just erase the disk and start over?

Last edited by xtian (2017-10-16 16:10:32)

fsckd · 2017-10-16 01:56:08

How did you unmount all those things?

xtian · 2017-10-16 09:10:55

I thought to reverse the mounting steps. unmount, vgchange, luksClose.

However, I recall I'd been working on this all day and just expected `umount` would say all the disks are busy.
I think I first deactivate the VG with `vgchange -a n` and then `umount`.

I do recall I received a new message. I got a maybe 8-word prompt asking me if I wanted to unmount the volumes. I typed 'y'.
But my memory is sort of fuzzy today. It could have said in eight words do I want to frack up my install? Duh. Yes.

The only LV that I couldn't unmount was root, and now it's the only one left.
Sorry I can't be more specific.

Last edited by xtian (2017-10-16 09:11:51)

fsckd · 2017-10-16 13:13:44

You certainly did more than you needed to in order to unmount. I have the feeling that in the process of "unmounting", you accidentally removed the volumes. But without knowing the exact commands you entered, it is hard to tell.

A few extra points I'd like to address,

(1) You do not need to manually unmount filesystems, deactivate volume groups, close luks containers, or deactivate swap before reboot. systemd (or openrc) handles that for you.

(2) Why was root busy? Were you doing this while booted into the system? Or were you trying to unmount everything while chrooted in the system?

(3) GRUB has nothing to do with this. GRUB has no more affect on LVM volumes than vim or chromium.

I advise you to change the thread title to something more applicable, like "missing LVM volumes" or whatever.

There's not much to go on with here. Give us the output of commands you've run, like {pv,vg,lv}display, lvscan, etc.

Moving to Newbie Corner as this is not an installation issue but an LVM management issue.

xtian · 2017-10-16 16:12:43

When you say, "you accidentally removed the volumes" do you mean delete?
If so then they're likely unrecoverable, and I should start over.

fsckd · 2017-10-16 16:17:48

Yeah, likely deleted. But without more information there's no way to know for sure what happened. Sorry we can't help more.

Arch Linux

#1 2017-10-15 22:35:16

Manually mount/unmount LVM from USB --now only one logical volume

#2 2017-10-16 01:56:08

Re: Manually mount/unmount LVM from USB --now only one logical volume

#3 2017-10-16 09:10:55

Re: Manually mount/unmount LVM from USB --now only one logical volume

#4 2017-10-16 13:13:44

Re: Manually mount/unmount LVM from USB --now only one logical volume

#5 2017-10-16 16:12:43

Re: Manually mount/unmount LVM from USB --now only one logical volume

#6 2017-10-16 16:17:48

Re: Manually mount/unmount LVM from USB --now only one logical volume

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