LVM shows 97% usage - is this expected?

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QMan

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Dec 23, 2018
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Hi all,

I'm fairly new to LVM storage, so looking for a bit of guidance. I currently have Proxmox installed on an Intel NUC with a NVME drive and a second SSD drive. Proxmox is installed on the NVME drive. I played around in Proxmox a bit setting up VMs and uploading ISOs, but I recently noticed that when I go to Proxmox > Datacenter > My Nuc device > Disks > LVM, the NVME disk shows 97% usage and 6 LVs (Logical Volumes?). My secondary SSD drive shows 0% usage and 0 LVs. I have since removed the ISOs from the NUC storage and removed all but 1 VM.

Is this expected? Based on what I understand of LVM so far, I'm guessing this means that 97% of the NVME disk is provisioned for use with LVM. Are the 6 LV's created by Proxmox as part of the install?

If anyone could confirm, or help educate me a bit on LVM I'd really appreciate it! Trying to make sure I have my Proxmox storage set up correctly before getting too many VMs running in the homelab :)

(If my storage configuration is messed up, is there an easy way to wipe/reset the disks or the LVM configuration without reinstalling Proxmox? I already have my 1 running VM backed up to a NAS device, so I'm not too concerned about that.)
 
By default Proxmox will use your install device as storage for VM's and containers. You need configure Proxmox post-install if you want to use additional storage options. If you add the SSD to the available storage list you will be able to migrate your VM's to SSD

Personally, I would consider installing and running Proxmox on the SSD and then use the NVME drive purely for VM's but that would mean wiping your current install
 
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bobmc said:
By default Proxmox will use your install device as storage for VM's and containers. You need configure Proxmox post-install if you want to use additional storage options. If you add the SSD to the available storage list you will be able to migrate your VM's to SSD

Personally, I would consider installing and running Proxmox on the SSD and then use the NVME drive purely for VM's but that would mean wiping your current install
Click to expand...

Thanks for the feedback and recommendation. For the time being, I think I will use the NVME drive for Proxmox, but I may certainly revisit that later.

I understand Proxmox will use the install device for storage of VMs and containers. Where I am still a bit unclear though is when I go to the LVM section, my NVME disk shows 97% usage and 6 LV's.

1.) Does 97% usage just mean that 97% of the disk is provisioned for use with LVM?
2.) How can I confirm what the 6 LV's (logical groups I believe) are? I'm assuming these are from the Proxmox install + my one running VM, but I wanted to confirm to make sure no Logical Volumes are left over from my old VMs which I have since removed.


Finally, when I check my NUC device under "Datacenter" I see my one running VM, and then I see my "NVME storage drive", as well as my "NVME storage drive-lvm". The entire drive is 500GB, but the "NVME storage drive" shows the total capacity as 100GB and the "NVME storage drive-lvm" as ~360GB. What is the difference between these two? Shouldn't there just be one NVME storage drive-lvm which is shows 485GB available (97% of 500GB)?

I apologize for all the beginner questions. Any help to better my understanding would be greatly appreciated!
 
Last edited:
Ah yes I see your confusion - the 97% refers to the percentage allocation of the volume group not to the space used within that volume

This is my nvme drive split into two partitions 600G/120G
Code: 
 pvs
  PV             VG       Fmt  Attr PSize    PFree
  /dev/nvme0n1p1 nvme_vmv lvm2 a--  <600.00g <99.75g
  /dev/nvme0n1p2 nvme_ctv lvm2 a--  <120.00g   1.76g
  /dev/sdg3      pve      lvm2 a--   <79.50g  <9.88g
Then this is the volume size on these partitions
Code: 
vgs
  VG       #PV #LV #SN Attr   VSize    VFree
  nvme_ctv   1   7   0 wz--n- <120.00g   1.76g
  nvme_vmv   1   7   0 wz--n- <600.00g <99.75g
  pve        1   3   0 wz--n-  <79.50g  <9.88g
So the nvme_ctv volume is fully allocated @99%

But the actual usage is only 65%
Code: 
lvs nvme_ctv
  LV            VG       Attr       LSize   Pool   Origin Data%  Meta%  Move Log Cpy%Sync Convert
  ctpool        nvme_ctv twi-aotz-- 118.00g               65.28  40.86
  vm-103-disk-0 nvme_ctv Vwi-aotz--   8.00g ctpool        27.10
  vm-201-disk-0 nvme_ctv Vwi-aotz--   8.00g ctpool        76.69
  vm-202-disk-0 nvme_ctv Vwi-aotz--   8.00g ctpool        62.86
  vm-203-disk-0 nvme_ctv Vwi-aotz--  62.00g ctpool        98.81
  vm-204-disk-0 nvme_ctv Vwi-aotz--   8.00g ctpool        12.02
  vm-205-disk-0 nvme_ctv Vwi-aotz--   8.00g ctpool        18.42
 
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Got it, thanks! This makes far more sense to me now. I really appreciate it!

I have just a few remaining questions to help me get on my feet:

1.) Is it normal to have a certain % of the disk not allocated towards the LVM? I'm assuming that space which is not provisioned is needed by the system for other purposes?

2.) When looking at the storage disks (in the Proxmox GUI) listed under my NUC device, I see "local" and "local-lvm" (both of which I believe are my 500GB NVME drive). The "local" storage disk looks to have 100GB capacity, while the "local-lvm" storage disk looks to have ~363GB. What is the difference between these two? Shouldn't there just be one "local-lvm" drive which shows 485GB available (97% of 500GB)?
 
bobmc said:
So the nvme_ctv volume is fully allocated @99%
Click to expand...

The only remaining question I have left is - your volume is fully allocated at 99% while my volume is at 97%. Obviously, this is not a huge difference (and in my case that 3% which is not allocated only amounts to a few GBs). But I'm just curious how that % is determined and if I should bother trying to get 99% or 100% allocation for that drive? I'm assuming at least some small % needs to be unallocated for the system?
 
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