"Number of LVs" and pve-data-tpool

[dxsew]

Hello,

I've been using PVE for a while as a small home server, and its great. I'm just doing a little tidying and I notice that the LVM disk is showing 98% full and 30 LV's. But, I have no where near that number - just three active and a few backups.

Can somebody please explain how the Number of LVs in the LVM view under Disks is calculated? Just want to ensure things are not duplicated etc.

Thank you.

 

[fabian]

you can check with lvs. note that snapshots of LVs are also LVs themselves

 

[dxsew]

Thank you. That makes sense in terms of where the 30 LV count comes from.

The LVM (under Disks on the server) shows a size of 1TB, 98% assigned to LVs. But, the 30 LVs are not all on one disk and are greater in size than 1TB.

Below is the result of lvs. How does this add up? The data LV is large, or are the other VMs inside the data LV? Rather confusing! Also, from this, what does the < sign signify?

Thanks, just trying to understand what is going on.

  LV                           VG  Attr       LSize    Pool Origin        Data%  Meta%  Move Log Cpy%Sync Convert
  data                         pve twi-aotz-- <794.79g                    83.37  4.21                           
  root                         pve -wi-ao----   96.00g                                                           
  snap_vm-100-disk-0_s20220107 pve Vri---tz-k    4.00m data vm-100-disk-0                                       
  snap_vm-100-disk-0_s20220506 pve Vri---tz-k    4.00m data vm-100-disk-0                                       
  snap_vm-100-disk-1_s20220107 pve Vri---tz-k   32.00g data vm-100-disk-1                                       
  snap_vm-100-disk-1_s20220506 pve Vri---tz-k   32.00g data vm-100-disk-1                                       
  snap_vm-101-disk-0_s20220109 pve Vri---tz-k   64.00g data vm-101-disk-0                                       
  snap_vm-101-disk-0_s20220506 pve Vri---tz-k   64.00g data vm-101-disk-0                                       
  snap_vm-101-disk-1_s20220109 pve Vri---tz-k  200.00g data vm-101-disk-1                                       
  snap_vm-101-disk-1_s20220506 pve Vri---tz-k  200.00g data vm-101-disk-1                                       
  snap_vm-103-disk-0_s20220109 pve Vri---tz-k   32.00g data vm-103-disk-0                                       
  snap_vm-103-disk-0_s20220506 pve Vri---tz-k   32.00g data vm-103-disk-0                                       
  swap                         pve -wi-ao----    8.00g                                                           
  vm-100-disk-0                pve Vwi-aotz--    4.00m data               0.00                                   
  vm-100-disk-1                pve Vwi-aotz--   32.00g data               99.46                                 
  vm-100-state-s20220107       pve Vwi-a-tz--   <8.49g data               46.03                                 
  vm-100-state-s20220506       pve Vwi-a-tz--   <8.49g data               45.81                                 
  vm-101-disk-0                pve Vwi-aotz--   64.00g data               58.74                                 
  vm-101-disk-1                pve Vwi-aotz--  200.00g data               46.94                                 
  vm-101-state-s20220109       pve Vwi-a-tz--   <8.49g data               46.17                                 
  vm-101-state-s20220506       pve Vwi-a-tz--   <8.49g data               43.81                                 
  vm-102-disk-0                pve Vwi-a-tz--   20.00g data               18.80                                 
  vm-103-disk-0                pve Vwi-aotz--   32.00g data               62.61                                 
  vm-104-disk-0                pve Vwi-a-tz--   32.00g data               13.48                                 
  vm-105-disk-0                pve Vwi-a-tz--   35.00g data               33.34                                 
  vm-901-disk-0                pve Vwi-a-tz--   64.00g data               100.00                                 
  vm-902-disk-0                pve Vwi-a-tz--   64.00g data               100.00                                 
  vm-902-disk-1                pve Vwi-a-tz--  200.00g data               100.00                                 
  vm-910-disk-0                pve Vwi-a-tz--    4.00m data               3.12                                   
  vm-910-disk-1                pve Vwi-a-tz--   32.00g data               97.34

 

[fabian]

the man page and our docs (1, 2)will answer a lot of those questions in more detail

but yeah, the short version - data is a thin pool, it reserves most of the space in the VG, but it itself contains thinly provisioned volumes. because these volumes are thin provisioned their total size can be bigger than the thin pool (or even the underlying VG/PVs), provided their usage does not exceed the thin pool size. this is called overprovisioning, and can be fine, as long as you monitor the situation to avoid (actually) filling up the storage - guests and often the storage itself don't like it when supposedly free and usable space doesn't actually exist, and data corruption is usually the result.