VM on lvm-thin with own lvm-thin?

[pes502]

Hello. I just completed my Proxmox + OPNsense installation (everything works fine now but of course I need to do some more work and research) but I have got (maybe) a very dumb question.

In my Proxmox I have a LVM-thin storage where my virtual machine is stored. It's fine. And now let's say that I want to install CentOS on that virtual machine. During the CentOS installation you need to choose how disk will be managed (viz included screenshot). Which option I should select? Because the machine itself is already on LVM-thin and I don't know, what will be the best choice here (If I need another LVM-thin inside the VM itself or if I should chose Standard) ... I am little bit lost in this.

So if anyone can explain me this "storage abstraction" I will be glad

PS: CentOS will be used as my test VM - no virtualisation i inside virtualisation or something like that.

 

[bbgeek17]

Thats the nature of the game, Proxmox uses LVM in most basic installation. In other cases it could be ZFS, or NFS, etc.

The OS you install will use LVM/ext/zfs/NTFS/etc. Dont overthink it. The most natural way to install is with LVM Thin. Its also the most flexible down the road. When you get more experience and are able to define your goals, or decide to squeeze the last microsecond from the write, you will make a more informed choice.

---

Blockbridge : Ultra low latency all-NVME shared storage for Proxmox - https://www.blockbridge.com/proxmox

 

[Kingneutron]

Everything is going to be thin-provisioned, so you don't need to use LVM inside the VM. LVM introduces an I/O slowdown / penalty and makes things more complicated than they need to be. Two levels of LVM will be even slower.

https://unix.stackexchange.com/questions/7122/does-lvm-impact-performance

Give Centos root 30GB to start with, and add separate virtual disks for whatever other partitions you expect to need (like /home or /var/www) and you can even add entire virtual disks to run ZFS in the guest. You can put these virtual disks on separate physical disks if you like, to make it a little more fault-tolerant and have separate I/O paths.

If you ever think you might want to shrink filesystems in-guest, use ext4 instead of XFS.

By allocating entire disks for partitions, it makes it way easier to grow/shrink things instead of having to mess around with LVM-specific commands in the terminal -- you can boot a rescue DVD and just use gparted after resizing the guest disk up (unless the filesystem is ZFS, then it's a little different.)