Can't use local-lvm / lvm-thin for Backups?

S

s3bbo

Member
Oct 19, 2021
9
1
8
55
I recently bought a second small form factor and installed ProxmoxVE on it. I am using PVE on another SFF computer, too and hadn't much challenges to have it doing what i want it to do.

But it seems something has changed and I maybe overlooked some option during the installation. I am using Linux for a few years now but never really spent time gathering much experience with LVM, so maybe my problem stems from lack of knowledge about this.

So, I want to just have a copy of my three VMs main-disk images - so should i f*ck up some configuration, i can just restore the backup and be fine with it. I don't mind this being on the same disk. It seems to me this is working fine on my old PVE server, but i can't add "Backup" as a storage type for the system Disk (nvme) of my new server.

I have two disks in the SFF computer
- 4TB nVME - should contain the PVE system and all that is necessary
- 4TB SSD (sda) - this one is passed through as a block device to one of the VMs


Code: 
root@luna:/# lsblk
NAME                         MAJ:MIN RM  SIZE RO TYPE MOUNTPOINTS
sda                            8:0    0  3.6T  0 disk
nvme0n1                      259:0    0  3.6T  0 disk
|-nvme0n1p1                  259:1    0 1007K  0 part
|-nvme0n1p2                  259:2    0    1G  0 part /boot/efi
`-nvme0n1p3                  259:3    0  3.6T  0 part
  |-pve-swap                 252:0    0    8G  0 lvm  [SWAP]
  |-pve-root                 252:1    0   96G  0 lvm  /
  |-pve-data_tmeta           252:2    0 15.9G  0 lvm 
  | `-pve-data-tpool         252:4    0  3.5T  0 lvm 
  |   |-pve-data             252:5    0  3.5T  1 lvm 
  |   |-pve-vm--200--disk--0 252:6    0   32G  0 lvm 
  |   |-pve-vm--100--disk--0 252:7    0   16G  0 lvm 
  |   |-pve-vm--100--disk--1 252:8    0  300G  0 lvm 
  |   `-pve-vm--300--disk--0 252:9    0  100G  0 lvm 
  `-pve-data_tdata           252:3    0  3.5T  0 lvm 
    `-pve-data-tpool         252:4    0  3.5T  0 lvm 
      |-pve-data             252:5    0  3.5T  1 lvm 
      |-pve-vm--200--disk--0 252:6    0   32G  0 lvm 
      |-pve-vm--100--disk--0 252:7    0   16G  0 lvm 
      |-pve-vm--100--disk--1 252:8    0  300G  0 lvm 
      `-pve-vm--300--disk--0 252:9    0  100G  0 lvm

So, the only place i can place backups in, is in the 96GB pve-root "partition" (or LVM thing)


Can i just mount the `pve-data-tpool` somehow? I am afraid to just try it and risking some data loss.

My Problem is basically, I cant - via the WEBGUI - assign "Backup" to the volume that has 95% space (`local-lvm`) - But i can in my old Proxmox VE.

Is there some trick?

TIA for any hints!
 
Backup requires "FILE" storage. That means there should be a file system where to place the files.
Local-lvm is BLOCK storage.

You can create a manual LVM slice (LV) from your "local-lvm", format it with your favorite file system, mount it, and point PVE to the mount as a "directory storage pool" (use is_mountpoint=yes).

Good luck

Blockbridge : Ultra low latency all-NVME shared storage for Proxmox - https://www.blockbridge.com/proxmox
 
  • Like
Reactions: Johannes S, Kingneutron and s3bbo
Thanks for your Reply.

So my understanding is that i have a Volume Group (VG) `pve` and a logical volume (LV) `data` making it pve-data.

In the `datacenter -> node -> disks -> lvm ` view, i can only see this one LV and it seems to allocate everything thats left of the disk? (filling it to 100%)

I can't find an option to add a "slice".

When you write "manual", do you mean to do it via commandline?

Would this mean i need to resize the existing data LV to have some space?

Code: 
root@luna:/# lvm lvs
  LV            VG  Attr       LSize   Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  data          pve twi-aotz--  <3.49t             11.08  0.87                          
  root          pve -wi-ao----  96.00g                                                  
  swap          pve -wi-ao----   8.00g                                                  
  vm-100-disk-0 pve Vwi-aotz--  16.00g data        53.40                                
  vm-100-disk-1 pve Vwi-aotz-- 300.00g data        100.00                                
  vm-200-disk-0 pve Vwi-aotz--  32.00g data        28.86                                
  vm-300-disk-0 pve Vwi-aotz-- 100.00g data        78.01          
                     
root@luna:/# lvm vgs
  VG  #PV #LV #SN Attr   VSize  VFree
  pve   1   7   0 wz--n- <3.64t <16.25g


I wondered whether i could just mount `|-pve-data 252:5 0 3.5T 1 lvm` (see lsblk output in previous post).

It seems not to be mounted, to me?

Code: 
root@luna:/dev/mapper# ls -al
total 0
drwxr-xr-x  2 root root     260 Jan 11 16:59 .
drwxr-xr-x 19 root root    4480 Jan 11 16:59 ..
crw-------  1 root root 10, 236 Jan 11 16:59 control
lrwxrwxrwx  1 root root       7 Jan 11 16:59 pve-data -> ../dm-5
lrwxrwxrwx  1 root root       7 Jan 11 16:59 pve-data-tpool -> ../dm-4
lrwxrwxrwx  1 root root       7 Jan 11 16:59 pve-data_tdata -> ../dm-3
lrwxrwxrwx  1 root root       7 Jan 11 16:59 pve-data_tmeta -> ../dm-2
lrwxrwxrwx  1 root root       7 Jan 11 16:59 pve-root -> ../dm-1
lrwxrwxrwx  1 root root       7 Jan 11 16:59 pve-swap -> ../dm-0
lrwxrwxrwx  1 root root       7 Jan 11 16:59 pve-vm--100--disk--0 -> ../dm-7
lrwxrwxrwx  1 root root       7 Jan 11 16:59 pve-vm--100--disk--1 -> ../dm-8
lrwxrwxrwx  1 root root       7 Jan 11 16:59 pve-vm--200--disk--0 -> ../dm-6
lrwxrwxrwx  1 root root       7 Jan 11 16:59 pve-vm--300--disk--0 -> ../dm-9

I just tried and just mounting did not work, probably for obvious reasons, but as i said, i am not too familiar with lvm :-/

Code: 
root@luna:~# mkdir pve-data
root@luna:~# mount /dev/mapper/pve-data /pve-data/
mount: /pve-data: wrong fs type, bad option, bad superblock on /dev/mapper/pve-data, missing codepage or helper program, or other error.
       dmesg(1) may have more information after failed mount system call.

I asked AI what to do and it told me to run something like this

Code: 
To add an LVM slice and mount it in Proxmox, follow these steps:

    Create a new logical volume (LV) in your existing volume group:


lvcreate -L <size> -n <lv_name> <vg_name>

So i wanted to have 1TB for backup...

Code: 
root@luna:~# lvcreate -L 1T -n backupstore pve
  Volume group "pve" has insufficient free space (4159 extents): 262144 required.



So if you would point me to how i add this "slice" to the lvm, I'd appreciate this very much.

I'm a little afraid if i just start resizing volumes or logical volumes i'll overwrite something by accident.

TIA
 
Last edited:
Try "lvreduce -L 2000G pve/data" which sets an *absolut* new size !!
After that you can do "lvcreate -L 1T -n backupstore pve".
Take a look at "pvs, lvs, lvdisplay" as you have some further blocks free which can be later used where it's needed.
After that create a filesystem on your new backupstore and mount it by fstab entry.
At last you can add it as directory in datacenter with your usage contents as wanted.
 
Last edited:
I would just setup Proxmox Backup Server in a VM and dedicate XGB of storage to it, leaving some space free (I would say at least 10-20GB) on the host. That is, if this is going to be the dedicated Backup server. You need enough space for PBS to do several versions of backup + dedup.

You can make the vm's root/boot disk ~8GB for PBS itself and give it a 2nd in-vm ext4 or XFS vdisk for datastore. Or if you're using LVM-thin for backing storage, create a single-disk ZFS pool in-vm. XFS is likely going to be the fastest option, but ZFS has features such as fast inline compression and snapshots.
 
You must log in or register to reply here.
Top Bottom