[pve-devel] CPU and Memory hot add

[Stefan Priebe]

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
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>>>