Open Stack

There are much bigger differences for why u should not over-provision
memory vs over-provision cpu.

But agreed in general you shouldn't use swap either.

There are many threads around how the OOM killer will get involved and why
you should avoid this...

- http://marc.info/?l=kvm&m=127375381631230&w=2
- http://www.spinics.net/lists/kvm/msg84799.html
- ...

On 12/23/13, 12:55 PM, "Cristian Falcas" <cristi.falcas at gmail.com> wrote:

>There is no point in using 8 virtual cores in compute node with 2
>cores. The same is valid for using swap as memory to reach the desired
>12gb.
>
>Of course, if you don't plan on using that machine for any real work,
>you can do it.
>
>
>
>On Mon, Dec 23, 2013 at 6:39 PM, Joshua Harlow <harlowja at yahoo-inc.com>
>wrote:
>> Nope, u can over provision on most all of the resources (CPU, ram,
>>disk) u
>> described there. Ram is the tricky one as the Linux oom killer may
>>start to
>> get involved when u push the ram limits to high. But there is nothing
>> stopping u from running 8 or more vms on a box, depending on the over
>> provision ratio u are ok with...
>>
>> Sent from my really tiny device...
>>
>> On Dec 23, 2013, at 3:55 AM, "Vikas Parashar" <para.vikas at gmail.com>
>>wrote:
>>
>> Thanks Cristian,
>>
>> Will elasticity  be limited to 4 Cores/4GB  (The max capacity of a
>>physical
>> host) ?
>>
>>
>> On Mon, Dec 23, 2013 at 5:00 PM, Cristian Falcas
>><cristi.falcas at gmail.com>
>> wrote:
>>>
>>> Hi,
>>>
>>> From what I know you can resize a machine, but this involves
>>> rebuilding the instance: openstack will create a snapshot of the
>>> machine an recreate the instance with the new snapshot and a new
>>> flavor. This is not very fast from my experience, so you will have a
>>> considerable downtime doing this, depending on the size of the current
>>> instance and how fast is your storage.
>>>
>>> Best regards,
>>> Cristian Falcas
>>>
>>>
>>>
>>> On Mon, Dec 23, 2013 at 12:03 PM, Vikas Parashar <para.vikas at gmail.com>
>>> wrote:
>>> > Hi,
>>> >
>>> > IaaS is all about elastic computing. I can stretch resources as per
>>>my
>>> > need
>>> > - increasing/decreasing the number of cores, RAM allocated etc..
>>> >
>>> > My question is - how does openStack achieve this elasticity for both
>>> > computation and RAM.
>>> >
>>> > If I create an image with 2 cores and 4 GB RAM (and one day I need to
>>> > increase this to, lets say - 6 Cores and 12 GB RAM), but all the
>>> > physical
>>> > hosts that I currently have (for Compute and RAM) at my disposal
>>>have a
>>> > max
>>> > of 4 Cores and 4 GB RAM each..
>>> >
>>> > Using openStack -
>>> >
>>> > a) is this possible (as long as the total cores and total RAM
>>>required
>>> > is
>>> > less than the group-total) ? If yes, how is this achieved.
>>> >
>>> > b) or the elasticity will be limited to 4 Cores/4GB  (The max
>>>capacity
>>> > of a
>>> > physical host) ? If no, then is it possible to achieve it ?
>>> >
>>> > _______________________________________________
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>>> > Post to     : openstack at lists.openstack.org
>>> > Unsubscribe :
>>> > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack
>>> >
>>
>>
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