Need to Extend LVE root. Please confirm I'm doing a live extension correctly

[Howz]

So the guy who setup Proxmox VE V7.4-16 on a Dell 720 has left the company and the sda3 pve-root has run out of space.
I am visually challenged and a Proxmox noob ut have some Rehat / Centos and limitied Devian exposure.
I've muddled my way through a number of posts on how this is done live and from what I can see this is similar to a Redhat 7 server that I successfully extended the root partition while live. There are however some differences between the Redhat and Proxmox VE environments.
There are a number of differences in the way in which storage is assigned whch are unfamiliar to me.

root@devops:/# df -h
Filesystem Size Used Avail Use% Mounted on
udev 48G 0 48G 0% /dev
tmpfs 9.5G 1.6M 9.5G 1% /run
/dev/mapper/pve-root 94G 94G 0 100% /
tmpfs 48G 43M 48G 1% /dev/shm
tmpfs 5.0M 0 5.0M 0% /run/lock
/dev/fuse 128M 24K 128M 1% /etc/pve
192.168.8.70:/volume1/pxmxbu/dump 8.8T 6.7T 2.1T 77% /mnt/pve/pxmxbu
//192.168.8.70/pxmxbu 8.8T 6.7T 2.1T 77% /mnt/pve/syncifs
tmpfs 9.5G 0 9.5G 0% /run/user/0
root@devops:/#


From what I can make out (and I may be wrong) the R720 has a RAID disk of capacity 6.2TB which is all assigned to the PV sda3 and the pve Volume Group

root@devops:/etc/apt# pvs
PV VG Fmt Attr PSize PFree
/dev/sda3 pve lvm2 a-- <6.55t <16.38g
root@devops:/etc/apt#

The root size is only 100GB

root@devops:/etc/apt# lvs
LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert
base-101-disk-0 pve Vri-a-tz-k 8.00g data 4.02
data pve twi-aotz-- <6.40t 5.51 1.06
root pve -wi-ao---- 96.00g
snap_vm-100-disk-0_kanbanFresh pve Vri---tz-k 16.00g data vm-100-disk-0
snap_vm-103-disk-0_clone_for_apbco pve Vri---tz-k 8.00g data vm-103-disk-0
swap pve -wi-ao---- 8.00g
vm-100-disk-0 pve Vwi-aotz-- 16.00g data 7.90
vm-102-disk-0 pve Vwi-aotz-- 58.00g data 76.87
vm-103-disk-0 pve Vwi-aotz-- 8.00g data 6.24
vm-104-disk-0 pve Vwi-aotz-- 8.00g data 8.03
vm-105-disk-0 pve Vwi-aotz-- 200.00g data 81.76
vm-106-disk-0 pve Vwi-a-tz-- 200.00g data 47.57
vm-107-disk-1 pve Vwi-a-tz-- 58.00g data 48.65
vm-108-disk-0 pve Vwi-a-tz-- 58.00g data 45.37
root@devops:/etc/apt#

My storage config

root@devops:/# cat /etc/pve/storage.cfg
dir: local
path /var/lib/vz
content vztmpl,iso,backup

lvmthin: local-lvm
thinpool data
vgname pve
content rootdir,images

nfs: pxmxbu
export /volume1/pxmxbu/dump
path /mnt/pve/pxmxbu
server 192.168.8.70
content backup,images
prune-backups keep-all=1

cifs: syncifs
path /mnt/pve/syncifs
server 192.168.8.70
share pxmxbu
content images,iso,rootdir,backup,snippets,vztmpl
prune-backups keep-all=1
username proxmoxbackup

root@devops:/#

The question I have is how do I extend the dev/pve/root volume with eg. 100GB

It would appear that the root volume is 100GB in size with the remaining 6.4TB assigned to the data volume.
Where do I get / make the 100GB free space I need to extend the root volume.

Please do not hesitate to request any additional information that may be required.

The server is used mainly to host LXC nodes for which I have backups.
I do not however have a bare metal restorable backup of the Proxmox VE installation.
Don't know how to do this on the current setup which backs uo to a Synology NFS share.
The bare metal restore backup is however a topic for another time. Extending the roor is more pressing.

Any assistance for a visually challenged noob will be greatly appreciated.

Thanks in advance.

 

[Howz]

Initially I thought it would be as easy as lvexntend -l +100GB /de/v/rve/root but that was before I noticed that the remaining 6.4TB had been assigned to the logical volume /data. Hence the topic of

Please confirm I'm doing a live extension correctly​

which no longer applies. I need assistance in adding an additional 100GB to /dev/pve/root.