[CentOS] LVM hatred, was Re: /boot on a separate partition?

Thu Jun 25 22:44:45 UTC 2015
Chris Murphy <lists at colorremedies.com>

Gordon Messmer gordon.messmer at gmail.com  Wed Jun 24 01:42:13 UTC 2015

> I wondered the same thing, especially in the context of someone who
> prefers virtual machines.  LV-backed VMs have *dramatically* better disk
> performance than file-backed VMs.

I did a bunch of testing of Raw, qcow2, and LV backed VM storage circa
Fedora 19/20 and found very little difference. What mattered most was
the (libvirt) cache setting, accessible by virsh edit the xml config
or virt-manager through the GUI. There have been a lot of
optimizations in libvirt and qemu that make qcow2 files perform
comparable to LVs.

For migrating VMs, it's easier if they're a file. And qcow2 snapshots
are more practical than LVM (thick) snapshots. The thin snapshots are
quite good though they take a lot of familiarity with setting them up.

Chris Murphy