[pve-devel] CPU and Memory hot add

[Alexandre DERUMIER]

>>Yeah found that. But this means that the vm allocates the value of max until the balloon guest driver is loaded. So if I set it to 128gb for each guest they can't boot together as each vm tries to use 128gb.

Are you sure of that ? Because, As Far I known (for linux guest), the memory is not allocated/filled at boot, and ballonning occur when the driver is loaded very fast at boot.
(For windows guest it's different, because it's zero filling the memory at boot)




----- Mail original ----- 

De: "Stefan Priebe - Profihost AG" <s.priebe at profihost.ag> 
À: "Alexandre DERUMIER" <aderumier at odiso.com> 
Cc: pve-devel at pve.proxmox.com 
Envoyé: Dimanche 16 Février 2014 10:28:27 
Objet: Re: [pve-devel] CPU and Memory hot add 


Am 16.02.2014 um 10:05 schrieb Alexandre DERUMIER <aderumier at odiso.com>: 

>>> ok so you addd maxcpus: 128 to each configto have it silently enabled? 
> 
> Yes ;) 
> 
> Just be carefull to set only 1 socket, as hotplug is core by core 
> 
> (I have also send pve-manager patches in the mailing, but dietmar don't have apply them yet 

Which ones? Can't find them. 

>>> How? set in config balooning to min and max to 4096 and then changing it 
>>> to 8192 for min max does not change anything in the guest. 
> 
> Set max to maximum "hotpluggable" memory 
> set min to current guest memory 
> set shares = 0 (that disable auto ballonning from pvestatd) 
> 
> Then play with min memory up/down 

Yeah found that. But this means that the vm allocates the value of max until the balloon guest driver is loaded. So if I set it to 128gb for each guest they can't boot together as each vm tries to use 128gb. 

Greets, 
Stefan 

> 
> 
> ----- Mail original ----- 
> 
> De: "Stefan Priebe" <s.priebe at profihost.ag> 
> À: "Alexandre DERUMIER" <aderumier at odiso.com> 
> Cc: pve-devel at pve.proxmox.com 
> Envoyé: Samedi 15 Février 2014 17:09:39 
> Objet: Re: [pve-devel] CPU and Memory hot add 
> 
> Am 15.02.2014 13:59, schrieb Alexandre DERUMIER: 
>> cpu hot add is already implemented. (even in proxmox ;) 
>> https://git.proxmox.com/?p=qemu-server.git;a=commit;h=838776ab650f0593b48c234070c1a189fdbd72c7 
>> 
>> cpu hot del is not yet implemented. (but they are some prelimary patches in the qemu mailing list) 
> 
> ok so you addd maxcpus: 128 to each configto have it silently enabled? 
> 
>> 
>> memory hotplug is not yet implemented. (should be ok for next qemu 2.0 release I think) 
>> 
>> But maybe they are cheating, like I do : just use ballonning with a fixed size ? 
> 
> How? set in config balooning to min and max to 4096 and then changing it 
> to 8192 for min max does not change anything in the guest. 
> 
> Stefan 
> 
> 
>> 
>> ----- Mail original ----- 
>> 
>> De: "Stefan Priebe" <s.priebe at profihost.ag> 
>> À: pve-devel at pve.proxmox.com 
>> Envoyé: Vendredi 14 Février 2014 21:18:47 
>> Objet: [pve-devel] CPU and Memory hot add 
>> 
>> Hi, 
>> 
>> while browsing the web, i found profitbricks, which is active in germany 
>> and the us (http://www.profitbricks.com/technical-info). 
>> 
>> They use KVM and offer memory and cpu hot add on the fly? Anybody an 
>> idea how this works if kvm does not already support it? 
>> 
>> Greets, 
>> Stefan 
>> _______________________________________________ 
>> pve-devel mailing list 
>> pve-devel at pve.proxmox.com 
>> http://pve.proxmox.com/cgi-bin/mailman/listinfo/pve-devel 
>>