How to expand LVM partition on Ubuntu 20.04?

Question

LVM

I welcome everyone.

When installing the Ubuntu 20.04 system on the server, I did not pay attention to the incorrect partitioning of the disks.
Raid 1 is configured from 2 disks of 1TB each. The total disk space is 900+Gb, and the system uses only 200Gb.

When trying to expand an LVM partition with the lvextend command, there were error messages about disk mappings and a duplicate Volume Group.
Can anyone come across this?

Answer 1

Corrected the description.
The total disk space is 900+Gb, and the system uses only 200Gb.