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.fal...@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 <harlo...@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.vi...@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.fal...@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.vi...@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 ? >>> > >>> > _______________________________________________ >>> > Mailing list: >>> > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack >>> > Post to : openstack@lists.openstack.org >>> > Unsubscribe : >>> > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack >>> > >> >> >> _______________________________________________ >> Mailing list: >>http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack >> Post to : openstack@lists.openstack.org >> Unsubscribe : >>http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack _______________________________________________ Mailing list: http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack Post to : openstack@lists.openstack.org Unsubscribe : http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack
