On 18-Dec-2012, at 8:54 AM, Mice Xia wrote: > Great feature and I believe a lot of customers need it, hope Xenserver will > support dynamic memory change one day. > > [Koushik] > Assuming that in the updated compute offering only CPU and RAM has changed, > the deployment planner can either select the same host in which case the > values are dynamically scaled up OR a different one in which case the > operation fails. In future if there is support for live migration (provided > HV supports it) then another option in the latter case could be to migrate > the VM first and then scale it up. > [/Koushik] >
Mice - Great point. But, I think when the vm is scaled up, allocators need to be wise enough to figure out if it could be adjusted on the same host or need live migration. I think atleast XS and Vmware support live migration (across clusters as well) now so dynamic scaling would have less probability of failing, but this could be an expensive operation because migrating volumes across clusters will be resource intensive. > For VMware, it supports memory overprovisioning, which means the total size > of VM's allocated memory can be larger than host's physical memory. Maybe we > can leverage it and reduce the chance to migrate VM before scale up. > > > Regards > Mice > > -----Original Message----- > From: Koushik Das [mailto:koushik....@citrix.com] > Sent: Sunday, December 16, 2012 1:44 AM > To: cloudstack-dev@incubator.apache.org > Subject: [DISCUSS] Scaling up CPU and RAM for running VMs > > Currently CS supports changing CPU and RAM for stopped VM. This is achieved > by changing compute offering of the VM (with new CPU and RAM values) and then > starting it. I am planning to extend the same for running VM as well. > Initially planning to do it for Vmware where CPU and RAM can be dynamically > increased. Support of other HVs can also be added if they support increasing > CPU/RAM. > > Assuming that in the updated compute offering only CPU and RAM has changed, > the deployment planner can either select the same host in which case the > values are dynamically scaled up OR a different one in which case the > operation fails. In future if there is support for live migration (provided > HV supports it) then another option in the latter case could be to migrate > the VM first and then scale it up. > > I will start working on the FS and share it out sometime next week. > > Comments/suggestions? > > Thanks, > Koushik
