kernel-5.14.0-427.el9    BUILT: Fri Feb 23 07:31:31 AM CET 2024
lvm2-2.03.23-2.el9    BUILT: Sat Feb  3 01:10:34 AM CET 2024
lvm2-libs-2.03.23-2.el9    BUILT: Sat Feb  3 01:10:34 AM CET 2024

First of all, this title seems like it should be rewritten:
   1. Using multiple volumes using same VDOPoolLV
       You can convert existing VDO LV into a thin volume. After this conversion you can create a thin snapshot or you can add more thin volumes with thin-pool named after orignal LV name LV_tpool0.

       Example
       # lvcreate --type vdo -L 5G -V 10G -n vdo1 vg/vdopool
       # lvconvert --type thin vg/vdo1
       # lvcreate -V20 vg/vdo1_tpool0


 # turned on (no warnings), but then this operation does NOT work.
[root@virt-021 ~]# grep thin_pool_autoextend_threshold /etc/lvm/lvm.conf 
        thin_pool_autoextend_threshold = 70     # edited by QA Thu Apr  4 05:11:29 2024
 
[root@virt-021 ~]# lvcreate --type vdo -L 5G -V 10G -n vdo1 vg/vdopool
    The VDO volume can address 2 GB in 1 data slab.
    It can grow to address at most 16 TB of physical storage in 8192 slabs.
    If a larger maximum size might be needed, use bigger slabs.
  Logical volume "vdo1" created.
[root@virt-021 ~]# lvconvert --type thin vg/vdo1
  Thin pool volume with chunk size 64.00 KiB can address at most <15.88 TiB of data.
  WARNING: Converting vg/vdo1 to fully provisioned thin volume.
Do you really want to convert vg/vdo1? [y/n]: y
  Converted vg/vdo1 to thin volume.
[root@virt-021 ~]# lvs -a -o +devices
  LV                  VG Attr       LSize  Pool        Origin Data%  Meta%  Move Log Cpy%Sync Convert Devices             
  [lvol0_pmspare]     vg ewi------- 16.00m                                                            /dev/sda(1283)      
  [lvol0_pmspare]     vg ewi------- 16.00m                                                            /dev/sda(1287)      
  vdo1                vg Vwi-a-tz-- 10.00g vdo1_tpool0        100.00                                                      
  vdo1_tpool0         vg twi-aotz-- 10.00g                    100.00 26.44                            vdo1_tpool0_tdata(0)
  [vdo1_tpool0_tdata] vg vwi-aov--- 14.30g vdopool            0.00                                    vdopool(0)          
  [vdo1_tpool0_tmeta] vg ewi-ao---- 16.00m                                                            /dev/sda(1280)      
  [vdo1_tpool0_tmeta] vg ewi-ao---- 16.00m                                                            /dev/sda(1286)      
  vdopool             vg dwi-------  5.00g                    60.03                                   vdopool_vdata(0)    
  [vdopool_vdata]     vg Dwi-ao----  5.00g                                                            /dev/sda(0)         
[root@virt-021 ~]# lvcreate -V20 vg/vdo1_tpool0
  Cannot create new thin volume, free space in thin pool vg/vdo1_tpool0 reached threshold.
 
 
 # turned off (warnings appear now) but this operation DOES work.
[root@virt-021 ~]# grep thin_pool_autoextend_threshold /etc/lvm/lvm.conf 
        thin_pool_autoextend_threshold = 100     # edited by QA Thu Apr  4 05:11:29 2024
 
[root@virt-021 ~]# lvcreate -V20 vg/vdo1_tpool0
  WARNING: Sum of all thin volume sizes (<10.02 GiB) exceeds the size of thin pool vg/vdo1_tpool0 (10.00 GiB).
  WARNING: You have not turned on protection against thin pools running out of space.
  WARNING: Set activation/thin_pool_autoextend_threshold below 100 to trigger automatic extension of thin pools before they get full.
  Logical volume "lvol1" created.
[root@virt-021 ~]# lvcreate -V20 vg/vdo1_tpool0
  WARNING: Sum of all thin volume sizes (<10.04 GiB) exceeds the size of thin pool vg/vdo1_tpool0 (10.00 GiB).
  WARNING: You have not turned on protection against thin pools running out of space.
  WARNING: Set activation/thin_pool_autoextend_threshold below 100 to trigger automatic extension of thin pools before they get full.
  Logical volume "lvol2" created.
[root@virt-021 ~]# lvcreate -V20 vg/vdo1_tpool0
  WARNING: Sum of all thin volume sizes (<10.06 GiB) exceeds the size of thin pool vg/vdo1_tpool0 (10.00 GiB).
  WARNING: You have not turned on protection against thin pools running out of space.
  WARNING: Set activation/thin_pool_autoextend_threshold below 100 to trigger automatic extension of thin pools before they get full.
  Logical volume "lvol3" created.
[root@virt-021 ~]# lvs -a -o +devices
  LV                  VG Attr       LSize  Pool        Origin Data%  Meta%  Move Log Cpy%Sync Convert Devices             
  [lvol0_pmspare]     vg ewi------- 16.00m                                                            /dev/sda(1283)      
  [lvol0_pmspare]     vg ewi------- 16.00m                                                            /dev/sda(1287)      
  lvol1               vg Vwi-a-tz-- 20.00m vdo1_tpool0        0.00                                                        
  lvol2               vg Vwi-a-tz-- 20.00m vdo1_tpool0        0.00                                                        
  lvol3               vg Vwi-a-tz-- 20.00m vdo1_tpool0        0.00                                                        
  vdo1                vg Vwi-a-tz-- 10.00g vdo1_tpool0        100.00                                                      
  vdo1_tpool0         vg twi-aotz-- 10.00g                    100.00 26.51                            vdo1_tpool0_tdata(0)
  [vdo1_tpool0_tdata] vg vwi-aov--- 14.30g vdopool            0.00                                    vdopool(0)          
  [vdo1_tpool0_tmeta] vg ewi-ao---- 16.00m                                                            /dev/sda(1280)      
  [vdo1_tpool0_tmeta] vg ewi-ao---- 16.00m                                                            /dev/sda(1286)      
  vdopool             vg dwi-------  5.00g                    60.03                                   vdopool_vdata(0)    
  [vdopool_vdata]     vg Dwi-ao----  5.00g                                                            /dev/sda(0)