On Sun, Feb 05, 2023 at 10:12:39PM +0000, Mike Larkin wrote: > On Sun, Feb 05, 2023 at 03:53:34PM -0500, Nick Holland wrote: > > On 2/4/23 17:31, latin...@vcn.bc.ca wrote: > > > Hello misc > > > > > > i am building an only VMD server: > > > > > > How could calculate the relation: CPU, Ram, Storage, VMs please? > > > > > > Thanks. > > > PD: > > > I have a Lenovo ThinkPad Edge 4 i3 cores, 500GB disk. 8GB Ram. > > > > > > > This is kinda virtualization 101 stuff, not really specific to OpenBSD. > > > > RAM: assume more than 1:1. The VM will require certain overhead, as will > > the base OS. So, if you want 2G VMs, you won't be getting four of them > > on your 8G machine. You might get three. (some VM systems support > > "thin provisioning" of RAM. This is really a great way to hurt yourself > > unless you really know what you -- and all your guest OSs -- are doing. > > And you are still really likely to hurt yourself). > > All vmm memory is wired, so do not overcommit memory with vmm/vmd. > > > > > Disk: Assume 1:1. Even if your VM system supports thin provisioning > > (OpenBSD doesn't appear to), don't. Assume you will use 100% of the > > Both supported formats (qcow2 and raw) are thin. But your advice is > sound; assume you will eventually use 100% of what you provision.
Here's what I meant by that: $ /export/VMs> vmctl create -s 100g big.raw vmctl: raw imagefile created $ /export/VMs> du -h big.raw 192K big.raw $ /export/VMs> ls -la big.raw -rw------- 1 mlarkin wheel 107374182400 Feb 5 14:20 big.raw Same holds true for qcow2. -ml > > > disk you provision for a VM. Because you will. Thin provisioning VMs > > is generally a bad idea. > > > > CPU: Test, don't speculate. This is where you can get some benefit from > > resource sharing. You can also end up fooling yourself into thinking > > that 10 VMs that are usually 90% idle can share one CPU, because that > > 10% busy time? They are all working on the same task. > > > > > > In your case of a 4xi3 8g/500g, I suspect your machine will run out of > > RAM, CPU and then disk, in that order, though if you work at it, you > > can run out in any order you wish. :) > > > > But it is all how you define your VMs and what you do with it. Your > > host i3 could be maxed out with a web browser, so the VMs you run are > > going to have to be minimal and your expectations modest. > > > > Nick. > > >
