In some cases you can't just power off the virtual machine to increase disk size on it, because, for example, a service is not yet HA configured but needs to be online 24/7, and root partition, doesn't have much space left on it. In such cases you have to increase the disk size on the fly.
Here we...
Sometimes you need to get/change/analyse some files/data/logs from the virtual machine which running under lvm.
We are going to mount the disk under Proxmox hypervisor, which is running debian as a base OS.
Imagine, we have situation like that:
lvs | grep vm
> > vm-100-disk-1 pve Vwi-aotz...