How to properly use disk space on a file server?

Question

Server equipment

There is a Proxmox hypervisor that runs on KVM. It has several VMs installed, including Debian with a file server. An additional 3 disks for the file archive are also connected, they are connected in RAID5 using mdadm. LVM hangs on the raid. This archive is connected by an additional disk to the file server.
And now the question itself ... Already on FS, how right! split the partition (s) in order to eventually get several network folders with the possibility of subsequent painless expansion of disk space?
For example:
1. One network folder will be 100GB, but in a month it will need to be expanded to 150GB.
2. Either I will connect another HDD, I will add it to the RAID on the hypervisor, I will also add it to the LVM group and increase this second disk connected to the VM
I tried to create 1 partition on the VM on this connected disk with the Linux LVM type but without VG and LV, picked up the ball, made folders, BUT it was not possible to manipulate the size of the folders.
I tried to create 3 different partitions with the Linux LVM type (each on a separate share), then I picked up the share... everything seems to be fine here, BUT when I increased the disk, I could not allocate free space to one of the partitions...
I tried to create only 1 partition with the Linux LVM type, create a VG on it and several LVs for separate balls, mounted these LVs, everything seems to be fine, but after the reboot the system stupidly stopped loading, did not understand, restored the backup.
In general, I still don’t quite understand the correct disk space layout scheme for network folders.

Answer 1

df -h
parted /dev/vdb
print
resizepart 1
500GB
resizepart 2
100GB
q
pvresize /dev/vdb1
lvscan
lvextend /dev/archive/public -l +100%FREE
resize2fs /dev/archive/public
df -h
more details can be found here