LVM better extend volume group or create a new one?

I am working on project to add space to an existing NethServer 6.10 installation without reinstalling.
I saw many hints on the community and now I am trying to put them all together.
The goal is to add two new disks in mirror and move ibay(s) on them.
From the experience of more skilled users than me is it better to add a new VG (say VolGroup01) ang create the new logical volume for ibay(s) inside it or simply expand VolGroup00 and create LV inside the original VG?
I am particularly interested in considerations on security/strength and performance of both solutions.
Thanks in advance.

I use LVM for this purpose, buy a new ssd, clone the old disk to the new one with dd, grow the pv to the max and grow the home (on my desktop) to the max

It always has been a dream for me because it is so simple

An example (in french) with raid and lvm

http://geekeries.de-labrusse.fr/?p=1556

I could get the working mirror, but I could not expand the PV. I will look into your doc, but (by chance) an English reference? (My technical French is a bit rusty :slight_smile: )
I think my problem is that NethServer installs both md1 and md2 and so I cannot add the full disk, but I must add the single partitions: md1–>sda1,sdb1 md2–>sda2,sdb2
When I get all synced on the two larger disks I don’t know how to expand sda2 and sdb2 so I can grow md2. If I can get there I think what pvresize, lvresize and resise2fs will do the rest (I did those succesfully but only adding new disks and not replacing).

this is an old documentation I made, english inside :slight_smile:

https://wiki.contribs.org/Raid:Growing