Sorry I don't use LVM enough to recommend any fault finding techniques... so unable to help.
The worst part will probably trying to find out the cause so it doesn't happen again.

However one thing to consider if you end up doing a re-install (if you haven't already).

While LVM brings with it much flexibility if also brings with it more complexity, and as you have unfortunately found out, a greater mess when things go wrong.

You can avoid LVM (it's the default) if you want during an install...

1. Select "I will configure partitioning"
2. On the partitioning screen find the words "New mount points to existing partitions after selecting them"
3. Directly under is a box with "LVM" and a down arrow to the right.
4. Click on the down arrow and select "Standard partition"
5. Create your partitions - naturally you will be need to know what sizes you require"

Here's mine done this way... no LVM.

[root@alex etc]# cat /etc/fstab



#

# /etc/fstab

# Created by anaconda on Tue Nov 22 16:14:34 2016

#

# Accessible filesystems, by reference, are maintained under '/dev/disk'

# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info

#

UUID=bcdd196c-66c6-44d5-878b-2d59e5672511 /                       xfs     defaults        0 0

UUID=bc4a40da-889d-4704-b307-ace6ec574b6e /boot                   xfs     defaults        0 0

UUID=9210e7e2-5630-4ba8-a9d4-4e051ef64afd /home                   xfs     defaults        0 0

UUID=8d51a525-7905-4170-8dd5-17062e98d987 /var                    xfs     defaults        0 0

UUID=730760eb-53f6-400f-bfa5-6ff4e140c11f swap                    swap    defaults        0 0

[root@alex etc]# 

If you require LVM - then by all means install it....

and finally I recommend at least 1G for boot as kernels are growing...

so, it seems /var completely deleted !!?? trying to mount the lvm on /mnt give me an access to /var/lock/lvm ?
I restarted the server because lost every connection to it, so noway to access it anymore .. and of course it failed at startup.

the error is :
creating directory '/var/lib/clearconsole/'.
No directory /var/lib/clearconsole/!
Logging in with home = '/'

-bash: /var/lib/clearconsole//.bash_profile: Permission denied

pffff im lost here.. any help is really welcomed

Have a nice week-end

I successfully mounted my partiton lvm_root but when I try to list the content, I just get a lock file... can I unlock it safely ?
Thanks