[pve-devel] saving kvm command line for migration

[Stefan Priebe - Profihost AG]

Am 19.02.2014 um 16:26 schrieb Dietmar Maurer <dietmar at proxmox.com>:

>> 1.) Block changes on a running VM through API - except hotplug is enabled
>> and the change is hotpluggable
> 
> OK for me.
> 
>> 2.) What about CPU? You don't need the hotplug feature for this. Right now
>> you need to manual add maxcpu setting to the conf. To have it straight i
>> would like to also only enable this if hotplug is set to 1
> 
> The goal is to make hotplug the default. It is just disabled because it is
> unstable for some features.
> 
>> 3.) I would like to store the generated command line of each start in the
>> command file to be sure at restore or migration the exact and correct
>> command line is used
> 
> I don't think that we should use that (as explained in the previous mail).
> 
>> 4.) For hot pluggable memory there is a way to get everything out of qom-
>> list and qom-get (sadly around 20 qom queries for each dimm / memdev).
>> Or to store memory / dimm adds in temporarily in config file until a vm is
>> newly started.
> 
> I would disable hotplup for that until it can be solved.

There are two ways to solve.

1.) easier to implement
Having a special conf value for temporary devices like memdev and dimmdev which will be cleaned on fresh start

2.) when saving a snapshot or migrate get all devs and details through qom-list and qom-get and store them into a special conf value. But this is very complex.

Stefan
>