VM’s Slow booting

gskger

@olivierlambert Out of curiosity, I carried out a few tests this weekend. My tests are not really scientific and must be taken with a grain of salt. I started with the bare metal installs, followed by the VM installs on the hypervisors. The current server ISOs have been used for OS or hypervisor installs. All OS or hypervisor were updated, but otherwise no tweaking was done (e.g. remove snap from Ubuntu).

The tests were carried out manually by starting the (bare metal/virtualized) OS and taking the time until the login prompt appeared. Where necessary, the grub menu was confirmed manually as quickly as possible. Up to three runs were averaged. The host is a HP ProDesk 400 G6 with a i5-10500T CPU, 32GB RAM and a KIOXIA 512GB M.2 NVMe SSD (KXG70ZNV512G). VMs had 2 CPU, 4 GB RAM and 32 GB storage.

Host	OS	Time to login [BIOS/EUFI in s]
bare metal	Ubuntu 22.04.4	-/39
	Debian 12.5	-/20
XCP-ng 8.2.1	Ubuntu 22.04.4	28/12
	Debian 12.5	18/8
Proxmox 8.1.4	Ubuntu 22.04.4	12/15
	Debian 12.5	10/10

Even if the differences are measurable, they don't have much significance for me in normal everyday operation. The result is still interesting though.

Edit: Added Time to login for EUFI boot on the hypervisors.

olivierlambert

Thanks @gskger Have you tried UEFI vs BIOS?

Forza

@bassopt said in VM’s Slow booting:

@olivierlambert hi, again!

Nah, as told before it’s on initramdisk. After loading grub. A Ubuntu test install I did freezes for almost 20 seconds there.

I do have some warnings when I boot xcp-ng regarding x-273 and x-297 .... would that cripple performance that much. ( consumer hardware )

Sounds like you have the wrong template. If you disable "quiet" option in grub (press e, then go to the kernel command line) you may see it is error out on enabling some hardware feature. I have seen it happen when trying to enumerate the CPUs. Have a look. You might be able to see in dmesg or journalctl too.

bassopt

@Forza I don’t use xcp-ng anymore. I have a machine i can install it to try out but I haven’t had time lately.

gskger

@olivierlambert Just updated my post with the BIOS vs. UEFI Time to login. Both hypervisors are equally fast with EUFI, although Ubuntu 22.04 on proxmox is now slightly slower. But I guess that is not realy relevant.

olivierlambert

That's interesting though