[pve-devel] CPU and Memory hot add

Alexandre DERUMIER aderumier at odiso.com
Tue Feb 18 07:01:53 CET 2014


>>ah profitbricks uses def. igor's patches ;-) 


yes, I see that :)


"Signed-off-by: Vasilis Liaskovitis <vasilis.liaskovitis at profitbricks.com>
Signed-off-by: Igor Mammedov <imammedo at redhat.com>"


Don't known why I don't work for you,
maybe I can try this week.

can you send me an howto for what need patching and qemu command line?



----- 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: Lundi 17 Février 2014 20:01:07 
Objet: Re: [pve-devel] CPU and Memory hot add 

ah profitbricks uses def. igor's patches ;-) 

Look at those: 
https://github.com/imammedo/qemu/commit/6ebb9556749f2e3950abbe1e9f9ae2d6dd268eec 

... 
/* 
+ * Memory hotplug ACPI DSDT static objects definitions 
+ * 
+ * Copyright ProfitBricks GmbH 2012 
+ * Copyright (C) 2013 Red Hat Inc 

... 

Stefan 

Am 17.02.2014 06:07, schrieb 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 
>>> 



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